Category: General Guidance

Requirements evolve. Language changes. Standards update. But the foundational concepts behind pipette calibration regulations remain consistent.

This guide is designed to educate you on the basics and point you to the appropriate sources for detailed regulatory interpretation, moving from:

Science → Competence → Recognition → Regulation → Oversight

The goal is to help you understand how these frameworks affect pipette calibration and documentation. We will cover the following topics:

NIST. CLIA. COLA. CAP. Joint Commission. ISO/IEC17025. ISO 8655. ILAC. GMP. GLP. SOP

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NIST

National Institute of Standards and Technology

What it is:

A U.S. federal agency that develops national measurement standards. NIST does not accredit laboratories. It provides the foundational measurement standards to which calibration results are traceable.

What this typically means for pipettes:

Calibration documentation should include:

• A statement of traceability to NIST
• Identification of reference standards used (the traceability chain)
• Evidence of controlled measurement processes

Traceability to NIST establishes the measurement foundation beneath your documentation.

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CLIA

Clinical Laboratory Improvement Amendments

What it is:

A U.S. federal regulation governing laboratories that test human specimens for diagnosis or health assessment.

What it cares about:

Accuracy. Reliability. Quality control.

What this typically means for pipettes:

CLIA does not prescribe a defined calibration format. However, laboratories must be able to demonstrate:

• The pipette is properly maintained and calibrated
• Ongoing tracking over time
• Date of calibration
• Equipment identification (serial or asset number)
• Pass/Fail determination
• Documentation of corrective action if out of tolerance

CLIA is outcome focused.
It requires evidence that equipment is controlled, monitored, and maintained.

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COLA

Commission on Office Laboratory Accreditation

What it is:
A laboratory accrediting organization operating under the CLIA framework, commonly serving physician offices and smaller laboratories.

What it cares about:
Defined procedures. Consistent documentation.

What this typically means for pipettes:
Documentation expectations are generally similar to CLIA

COLA is outcome focused.
It requires evidence that equipment is controlled, monitored, and maintained.

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The Joint Commission

What it is:

An accrediting body for healthcare organizations and hospital laboratories.

What it cares about:

Risk management. Equipment control. Patient safety.

What this typically means for pipettes:

The Joint Commission requires a defined maintenance and calibration program, including:

• A documented calibration and maintenance plan
• Date of calibration
• Equipment identification (serial or asset number)
• Pass/Fail documentation
• Traceability
• Documentation of corrective action (if out of tolerance)
• Evidence of program oversight

The Joint Commission is system focused.
It evaluates whether your maintenance program is clearly defined and consistently followed, not just whether calibration occurred.

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CAP

College of American Pathologists

What it is:

A laboratory accreditation organization that often exceeds baseline CLIA requirements.

What it cares about:

Defined intervals. Traceability. Data defensibility.

What this typically means for pipettes:

CAP requires a clearly defined maintenance and calibration program and the technical calibration data to support it:

• Calibration at defined intervals
• Documented tolerances
• Traceability to recognized standards
• Equipment identification (serial or asset number)
• As-Found (AF) and As-Left (AL) data, not just Pass/Fail
• Statistical accuracy and precision values
• Documentation of out-of-tolerance events

CAP inspections are typically checklist driven and may require detailed calibration data to support technical defensibility.

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ISO/IEC 17025

What it is:

The international standard for testing and calibration laboratory competence.

What it cares about:

Laboratory competence. Technical validity. Measurement uncertainty. Traceability. Quality systems.

When a calibration provider is ISO/IEC 17025 accredited, documentation typically includes:

• As-Found (AF) data
• As-Left (AL) data
• Defined tolerances
• Measurement uncertainty
• Traceability statements
• Environmental conditions (if required)
• Accreditation identification

The documentation carries international recognition when the accreditation body is an ILAC Mutual Recognition Arrangement (MRA) signatory.

This matters most in pharmaceutical, biotechnology, manufacturing, and global trade environments.

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ISO 17025 Accreditation Status Variations

ISO 17025 Accredited via ILAC MRA Signatory

A third-party accreditation body has audited the laboratory and issued ISO/IEC 17025 accreditation. The accrediting body is a signatory to the International Laboratory Accreditation Cooperation Mutual Recognition Arrangement (ILAC MRA), providing international recognition of the accreditation and strengthening confidence in calibration results across regulatory jurisdictions. This distinction is particularly important in pharmaceutical, biotechnology, manufacturing, and international trade environments.

ISO 17025 Accredited (Non-ILAC MRA)

A third-party accreditation body has audited the laboratory and issued accreditation. However, the accreditation body may not be internationally recognized under the ILAC framework. Accreditation is verified, but international recognition may be limited.

ISO 17025 “Compliant”

The laboratory states its internal quality system aligns with ISO 17025 principles. There is no third-party accreditation audit. Documentation depth may vary and is not independently verified.

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ISO 8655

What it is:

The international standard defining performance requirements and test methods for piston-operated volumetric apparatus (pipettes).

What it cares about:

Instrument performance. Accuracy limits. Precision limits. Standardized testing methods. Defined error calculations. Controlled environmental conditions.

When calibration follows ISO 8655, documentation typically includes:

• Defined gravimetric test method
• Defined test volumes
• Calculated accuracy values
• Calculated precision values
• Comparison to maximum permissible error limits

ISO 8655 defines how the pipette should be tested.
ISO/IEC 17025 defines whether the laboratory is competent to perform that testing.

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GMP

Good Manufacturing Practice

What it is:

A regulatory framework governing pharmaceutical, biotechnology, and medical device manufacturing.

What it cares about:

Product quality. Process control. Risk mitigation.

What this typically means for pipettes:

• Controlled measuring devices
• Defined calibration intervals
• Traceability to national standards
• Documented review process
• Impact assessment if out of tolerance

Under GMP, the key question becomes: Could an inaccurate pipette affect product quality?

Documentation must support defensibility.

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GLP

Good Laboratory Practice

What it is:

A framework governing non-clinical research and safety studies.

What it cares about:

Data integrity. Study validity.

What this typically means for pipettes:

• Evidence equipment was suitable for use
• Retained calibration documentation
• Traceability
• Support for reproducible results

GLP protects the validity of reported data.

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SOPs

Standard Operating Procedures

The governing internal documents that define how your organization operates.

What it cares about:

Consistency. Defined processes. Accountability. Documentation control.

What this typically means for pipettes:

Your SOPs define:

• Calibration intervals
• Acceptable tolerances
• Required documentation depth
• Review and approval processes
• Record retention requirements
• Out-of-tolerance response procedures

Inspectors and auditors will evaluate: Are you following your own written procedures?

Regulations and accreditation standards establish minimum expectations. In many environments, failure to follow internal SOPs is a larger finding than the regulatory citation itself.

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In Summary

While CLIA, CAP, ISO, GMP, and GLP provide the framework, your organization determines:

• The level of documentation required
• Whether AF/AL data is required
• Whether uncertainty statements are necessary
• Whether ISO 17025 accreditation is mandated
• Whether ILAC MRA recognition is required

Each laboratory has the responsibility to define what is appropriate based on:

• Risk level
• Patient impact
• Manufacturing impact
• Research integrity
• Customer requirements
• International distribution

The key is not memorizing acronyms. It is understanding how they connect.

Regulations establish the framework. Accreditation verifies competence. NIST anchors traceability. SOPs define your Internal Standard.

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Instrument Use Cases

Pipette:

Pipettes are used to transfer small amounts of liquid, usually ranging from 0.1 µL and up to 10,000 µL.  They are the preferred measuring instrument in situations where accuracy and precision are essential. The pipette comes in single and multichannel options. The single channel mechanical pipette is known to be the workhorse in every life sciences laboratory worldwide.  You’ll typically find a set of them on every technician’s lab bench.

Controllers:

Pipette controllers are used with serological pipets for quickly and repetitively filling and releasing volumes of liquid. These devices offer ambidextrous capabilities and include different function modes and speed dials to adjust for different liquid volumes and viscosity. Controllers are the preferred instruments when repeatedly dispensing larger volumes (typically 1-100mL). The accuracy of the dispensed liquid is controlled by the manual manipulation of the dispense/aspirate controls.

Repeaters:

Repeaters are used to repeatedly dispense the same volume of liquids multiple times without having to aspire in between. They are more accurate than controllers and are typically used for volume ranges between 1µL and 50mL.

Bottletop Dispensers / Burrettes:

Bottletop dispensers are the best way to dispense aliquots of liquid from large glass or plastic bottles. The bottletop burette’s job is to provide reproducible dispensing without wasting reagents.

Positive Displacement Pipettes:

Positive displacement pipettes are the best tool for use with liquids that render traditional air-displacement pipettes ineffective. The piston directly expels the media from the tip, wiping the tip walls completely clean. This results in negligible residual wetting and highly accurate, reproducible results, especially with viscous, foaming, high-vapor-pressure, and other “problematic” liquids. They are excellent tools for applications in wastewater treatment plants, biochemical, genetics and molecular biology laboratories, wineries, breweries, refineries, and more.

Related Posts:

How to Find Your Part Online
Types of Pipette Tips
Top 10 Crimes Committed Against Pipettes
Pipette Parts – Life Span, Life Cycle, and Performance

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Our website has multiple ways to find the part you need. The best search method will depend on what information you already have.

If you have the part number:

Enter the part number in the search bar.

If you have the pipette model name:

Search the ‘Replacement Parts’ tab for your pipette model. For example, if you are working with Rainin’s Pipet-Lite XLS Single Channel, you would search under the ‘P’ tile for ‘Pipet-Lite XLS’. From there, you will find all the available parts.

If you have neither, but you know the manufacturer name:

Use the ‘By Brand’ tab to search by pipette manufacturer. Click into the ‘Pipette Parts’ category and review the pipette model pictures to find yours. Click through the subsequent categories to find the part you need.

If you are having trouble finding your part, contact us and we’ll be happy to help.

Related Posts:
Top 10 Crimes Committed Against Pipettes
Types of Pipette Tips
Pipette Parts – Life Span, Life Cycle, and Performance
Non-Linear Volume Readings – When Should A Calibration Adjustment Be Made?

Pipette lingo can get confusing. Stay in the know with these different types of pipette tips.

Low Retention

• Low retention tips are for applications requiring high accuracy and reproducibility. They reduce sample retention by 3-5 times when compared to ordinary tips. Good for use with samples that contain detergents.

Graduated Tips

• These tips have scale lines along the tip, which makes it easy to infer the amount of liquid in the tip. Example: Indicators for 50μl, 100μl, 200μl.

Filter Tips

• A small filter rests in the top of the tip to ensure no aerosols or liquid can reach the pipette shaft. Permeability is controlled by the pore size and filter length.

Extended Length/Elongated Tips

• Designed to be used with narrow or deep vessels. They keep the pipette from touching the walls of the vessel and prevent cross-contamination.

Wide Orifice/Widebore Tips

• The wide orifice prevents mechanical shearing that can cause cell fragmentation. These tips are good for use with cell suspensions and macromolecules (including DNA).

Universal Tips

• Along with the tip manufacturer’s pipettes, these tips are also designed to fit *most* other manufacturer’s pipettes. Please note, these tips are not guaranteed to fit all other manufacturer’s pipettes.

ClipTip Tips

• ONLY compatible with ClipTip pipettes (Thermo Fisher)

LTS Tips

• ONLY compatible with LTS pipettes (Rainin)

Beveled Tips

• These types of pipette tips have a sloped edge around the opening which reduces sample hang-up.

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

How to NOT use a pipette:

#1: Not Proactively Replacing Common Parts at Routinely Scheduled Intervals:

Pipettes must have common parts replaced routinely. The following pipette parts should be inspected, tested, and replaced proactively in order to maintain good accuracy and precision.

• Seal and o-ring: The internal polyethylene seal begins to wear and needs replacing at least once every year (12 months. The rubber o-ring is typically more durable and typically should be replaced every 1-2 years (12-24 months). If you’re replacing the seal, it is recommended to replace the o-ring at the same time to allow both parts to wear/break-in together. Pipette Supplies, Inc stocks and sells many different pipette models seals and o-rings.
  
• Pipette Shaft: The pipette shaft is highly durable, but should be replaced every 2-3 years (24-36 months). Over time the constant friction of loading and ejecting pipette tips, chemical splash from liquids, etc. begins to wear down the shaft enamel, causing the pipette tip to potentially slip and not seal as strongly as designed. Internally, the shaft can become pitted or scratched and prevent the seal and o-ring from sealing properly, leading to liquid leaking from the tip.
  • Think of pipette shafts like your teeth enamel. Liquids, friction, and acids from food and drink attack and try to wear down teeth enamel. Without routine brushing and flossing your teeth enamel can become compromised. The same is true with the pipette shaft and can lead the pipette to not fully aspirate and dispense the desired volume, thus impacting accuracy and precision.

• Piston Assembly: The internal piston assembly should be replaced every 3-4 years (36-48 months). Piston materials vary by pipette manufacturer. Pistons are typically made of 316-gauge stainless steel, porcelain/ceramic, plexus-glass, or other high-grade plastics. The process of aspirating and dispensing liquids takes its toll on the piston assembly, especially when vapors, aerosols, chemical splash, etc. come in contact with the piston assembly and piston lubricant (on those models that require it).
  
  When liquids or chemical splash come in contact with the piston, it can cause the stainless-steel piston to rust, corrode, become scratched, and change the consistency of the piston lubricant (if applicable). Also, repeated autoclaving of the pipette and piston assembly may expand and contract the plastics of the piston. Long term, the piston may not be as linear/straight as it was when new.
  
  
• Pipette Lubricant: Some pipette models use a high-grade lubricant on the internal piston assembly, seal, and/or o-ring. Not all lubricants are alike and is recommended that only the recommended manufacturer lubricant be used. On most models that require lubricant, it is recommended that the lubricant be removed, parts cleaned, and re-lubricated with the manufacturer’s recommended lubricant at least once every 6 months (1/2 year). Lubricant is like a magnet and attracts dust, vapors, aerosols, and chemicals.
  • Over the course of use and operation, the lubricant can migrate and become dirty due to chemical splash, vapors, aerosols, etc. This is highly visible if this has occurred, as the pipette would visibly leak when set to the nominal volume. Keep the lubricant clean to ensure good accuracy and precision.

• Batteries (Electronic Pipettes): Over the years, pipette manufacturers commonly selected Nickel Cadmium (Ni-Cd), Nickel Metal Hydride (Ni-mH), Lithium-Ion (Li-Ion), etc., as their preferred batteries of choice. The style of battery is imprinted on the battery itself.
  • Recharging of Ni-Cd batteries have a high memory effect and should only be recharged once the battery is depleted. Consistent recharging of the battery when not depleted or left sitting on the charging stand will degrade the battery life cycle. Most Ni-Cd batteries last 1-2 years for the simple fact that the end user does not let the battery fully deplete itself before recharging. Once the battery is fully recharged, unplug the stand.
  • Recharging of Ni-mH batteries have a moderate memory effect and like the Ni-Cd batteries should only be recharged once the battery is depleted. Consistent recharging of the battery when not depleted or left sitting on the charging stand will degrade the battery life cycle moderately. Most Ni-mH batteries last 2-3 years. Once the battery is fully recharged, unplug the stand.
  • Recharging Lithium-Ion (Li-ion) batteries have a low memory effect and can be left on the charging stand or recharged when not fully depleted. Most Li-Ion batteries have a small PCB chip embedded into the battery that will allow to top off the battery when recharging and not accept any further recharging when fully recharged. This means the battery will not shut itself off when fully recharged, thus protecting itself and life cycle. Most Li-Ion batteries last 3-5 years.

#2 Not Storing Pipettes Vertical When Not in Use:

Pipettes like to be stored vertically! Be good to your pipettes and store them on a pipette stand, in the middle of the lab bench away from edges and opportunities to be knocked off.

Placing a pipette horizontally on the lab bench, in a drawer, on the counter, etc. can increase the probability of damage to the pipette shaft, body, and plunger rod. Pipettes stored horizontally are more costly to keep accurate and precise than pipettes stored vertically.

#3 The Selection of Non-Manufacturer Tips -Versus – Manufacturer Tips:

Tight budgets and spending restrictions are common in most labs. Selection and procurement of pipettes tips is one of the most common overlooked crimes against pipettes. Many of us know very little about the intricacies of pipettes, pipette tips, and filtered tips. If the tip fits and allows for the aspiration and dispensing of liquids, then it must be okay, right? Not exactly.

Most pipette manufacturers engineer, injection mold, and publish their accuracy and precision specifications for their pipettes when used with their tips. However, published accuracy and precision specifications may or may not be obtained when using manufacturer pipette tips with a competitor pipette. Most pipette and tip manufacturer’s leave it to the lab technician, supervisor, manager, or purchasing agent to decide if the desired volume delivered will meet their internal requirements, SOP’s, and expectations.

Think about this before placing your next pipette tip order:

• Are you purchasing the same manufacturer tips as your pipette?
  • Using manufacturer tips on the same manufacturer’s pipette (for example: Gilson Diamond tips with a Gilson Pipetman, or Eppendorf Research-Plus with Eppendorf EP tips) will provide the best accuracy and precision results, guaranteed! Why? The tips are engineered and designed to fit, form, seal, and deliver the best results over and over again. The problem lies when manufacturer tips are used with a pipette from a different manufacturer. Why? Once again, manufacturers design their tips to deliver the best results when used with their pipettes. When different pipettes and tips are interchanged, end users can typically expect up to a 10% margin of error in the volume aspirated and dispensed due to different variables. This could be due to the differences in:
    • Micron size of the filter to allow air flow to permeate and pass (if filter tips are used).
      The smaller the pore size of the micron <20um, the greater restriction of air-flow through the filter
    • Tip orifice size (wide orifice, normal orifice).
      Wide orifice tips have larger swings in both accuracy and precision due to larger orifice. The larger the orifice opening, the more liquid that wants to enter or leave
    • Thin-walled tips, thick-walled tips, yip orifice beveled/orientation.
      When dispensing, liquids like to cling to beveled and thick wall tips. This can have an impact on accuracy and precision. Thin-walled tips allow for better dispensing and droplet touch-off.
    • Embedded tip sealing ring(s) location when sealing to a pipette shaft. The internal tip sealing ring is in different locations on different manufacturer’s tips. This may prevent the tip from properly sealing to the shaft fully and allowing desired aspiration and dispensing with the pipette.
    • Type of liquid aspirated & dispensed (aqueous, dense, volatile, viscous, high-surface tension). Air displacement pipettes excel with aqueous-like liquids and can be impacted by other liquids. The internal air cavity inside the shaft will not allow the pipette to achieve proper aspiration or leak with non-aqueous-like liquids. If the air cavity is weaker than the liquid aspirated, you selected the incorrect pipette. When the liquids are dense, volatile, viscous, or have high surface tension, use a positive displacement pipette.
• Does your application assay require the use of filtered pipette tips?
  • Not all filtered tips are the same. Do your research to ensure that the filtered tips will meet your specific application needs. This includes but is not limited to:
    • What material is the tip filter made from? Most filters are made from molded polyethylene or use a cellulose gum additive (i.e., self-sealing when it gets wet). Some filters may flake or leach out and potentially compromise your samples.
    • What is the average pore size of the tip filter being used? Air-displacement pipettes require the displacement of air in order to aspirate and dispense your sample. Most tip manufacturer’s filters are between 25microns -45+ microns that will successfully allow air to permeate through the filter in order to aspirate and dispense your sample. Once the pore size of the filter decreases lower than 20 microns or smaller, then the air flow needed in order to aspirate and dispense liquids becomes more restricted. This may lead to lower-than-expected volumes of liquids aspirated and dispensed.
    • Self-Sealing Filters: Are a great concept, but only work when they get wet. If a portion of the filter gets wet, it will self-seal and limits air flow. Of course, this is mostly obvious if the entire filter becomes wet because no liquid will be aspirated.
• Does your application assay require the use of low retention tips?
  • Low retention tips are great in helping to fully expel costly liquids from the tip or those liquids that are troublesome at fully dispensing. Many tip manufacturers either injection mold or dip their tips into a fluoropolymer like fluoropel to give them low retention properties. Keep in mind that if using low retention tips at volumes of 5uL or lower, the probability of aspirating and dispensing the desired volume may be lower than expected. Most fluoropel proprieties are gone after 1-3 aspiration and dispensing cycles.
• Does your application require the use of wide orifice (wide bore) tips?
  • Wide orifice tips have a slightly larger tip orifice opening. Wide orifice tips are great when aspirating and dispensing viscous, dense, high surface tension liquids that get caught up at the tip orifice with a normal sized tip orifice. However, wide orifice tips have a tendency to aspirate and dispense slightly more liquid during the pipette cycle due to the larger tip orifice. This may impact the accuracy and precision of the pipette used under test. The pipette gets the blame when the volume delivered is not what was expected. Be sure that it is not the wide orifice tip. Also, wide orifice tips should not be used for the calibration of pipettes for the same reason. The accuracy and repeatability may not be as good as expected when compared to a normal tip orifice pipette tip.
• Do you autoclave your tips?
  • The common concern with autoclaving tips is that they are autoclaved multiple times. Pipette tips should be autoclaved ONLY once at 121°C for 10 minutes with a 5-minute drying cycle at 110°C. Filtered or presterilized tips NEVER should be autoclaved as the process of becoming sterilized through gamma radiation or electron-beam radiation could make the polypropylene tips brittle and crack if autoclaved. Not to mention, the tip filter will become brittle and flake during the autoclaving process.
• Do you store your tips under UV light?
  • Pipette tips can be stored in a hood under UV light in a pipette tip rack with the lid closed. Leaving the rack uncovered for an extended period of time with the UC light on will make the tips brittle and crack, especially when loading a tip onto a pipette shaft. Also, the internal sealing ring in the pipette tip may become compromised if expose to UV light for an extended period of time in an uncovered rack. UV light can impact tips, thus providing compromised accuracy and precision results that are often a crime blamed on the pipette.

#4 Not Adhering to Good Pipetting Techniques:

Learning, using, and maintaining good pipetting techniques is vital to the life and longevity of any pipette. The following pipetting techniques below will help put you on the road to providing your pipettes with a long life.

• Reduce mechanical back-lash: Mechanical back-lash is the art of setting the pipette to its desired volume. Most mechanical pipettes have a three- or four-digit volume display and the spacing (commonly referred to slop) in-between the digits can lead to minor volume mis-settings. Winding the pipette 1/3 of a turn above the desired volume (i.e., 203uL ad then back to 200uL) will help minimize mechanical slop in-between the dials. Thus, the desired volume delivered should be slightly more accurate. Every little bit helps, right?

• Pre-Rinse at least twice for aqueous-like liquids: Pipette tips are equilibrated to air temperature and are hydrophilic. By wetting the tip through two prerinses at the desired volume makes the tip hydrophobic and wettable. Also, the tip is now equilibrated as close to the aqueous-like sample temperature. Pre-rinse of at least two times, can improve accuracy up to 0.2% of the desired volume under test. Water versus air temperature may vary from 0.5-1.0°C. By prerinsing at least twice helps to minimize evaporation impacts and deliver better accuracy and precision.

• Tip immersion depth:One of the common mistakes end user make that lead to larger swings in accuracy and precision is not following industry-wide tip immersion depths. Adopting this will aid in delivering better accuracy and precision. Recommended tip immersion depths by nominal volume are below. This means submerge the pipette tip “x” mm beneath the surface of liquid before aspiration:
  • 2uL -10uL: 1-2mm
  • 20uL -50uL: 2-3mm
  • 100-300uL: 3-4mm
  • 1000uL – 2000uL: 4-6mm
  • 5000uL and up: 6-12mm

• Pipetting verticalness: Not holding the pipette vertical during aspiration and dispensing may lead to inaccurate volumes. This means you may aspirate too little, too much or not fully get all of the liquid out of the tip during dispensing. Holding the pipette greater than 20% of vertical exacerbates the volume aspirated and dispensed, and may lead to up to 0.2% less volume.

• Reduce hand-warming: Holding and using a pipette (especially in gloved hand) for at least 15-30 minutes non-stop can impact the amount of volume aspirated and delivered. As we know already, air-displacement pipettes use a partial air cavity in order to aspirate and dispense liquids. When the air cavity gets heated through our hands, it will expand, causing the liquid aspirated and dispensed to be less.  By holding the pipette loosely, using the finger hook (if applicable) or placing the pipette in the stand in-between pipetting cycles, will minimize hand warming impacts. Pipetting 30 minutes consecutively may impact accuracy of the desired volume under test by 0.2% or more. Don’t let your pipette air cavity get warm.

• Speed, time, smoothness, and care: Establishing a good pipette rhythm is helpful to ensure good accuracy and precision. Do it the same way every time. Care is given to not aspirate and dispense too fast. When aspirating, gently control the aspiration upward with mechanical pipettes and pause 1-2 seconds after full aspiration to ensure that a full aspiration is received before removing your tip from the sample. Not pausing could lead to air bubble, or not achieving a full aspiration.
  • Dispensing should be in a smooth, controlled rhythm to ensure the sample flows smoothly out of the tip. When the sample is fully dispensed, pause 1-2 seconds, then proceed to blow-out and touch off against the side the reservoir. Not pausing before blowout and then touching off may impact the amount of volume delivered, especially if the tip is a thick-walled tip or has a beveled orifice that may have liquid clinging to it after dispensing.

• 60-Second pipette liquid sealing system test: On a routine basis, based on frequency of use, end users should conduct a 60 second leak test to confirm there are no visible leaks with the pipetting sealing system. This can be accomplished as such:
  • Set the pipette volume to nominal (i.e., 100% volume)
  • Fully load a pipette tip onto the shaft
  • Immerse the tip into deionized water or distilled water at the recommended tip immersion depth
  • Gently aspirate liquid into the tip in a smooth, controlled rhythm. Pause 1-2 seconds after full aspiration
  • Remove the tip from the sample and hold the pipette loosely by the finger hook or body and count to ten. We are looking for any visible leaks from the pipette tip orifice.
  • If no leaks are detected, the internal sealing system is maintaining a proper air vacuum.
  • Lastly, visibly inspect the exterior of the shaft for wear, scratches, marks, etc. where the pipette tip seals to the shaft.

If a leak is detected, please contact Pipette Supplies, Inc for additional troubleshooting support and possible part(s) replacement.

#5 Not Performing Routine Preventive Maintenance and Calibration:

Pipettes require routine preventive maintenance and verification to ensure accuracy and precision are maintained. Common replacement parts that customers can replace include but are not limited to: seals and o-rings, shafts, piston assemblies, and lubricant as needed.

The accuracy and precision of a pipette should be verified at least once every year (12 months), based on frequency of use, or every 6 months for pipettes that use internal grease lubricant on the piston assembly (i.e., 5000uL and larger sizes).  This includes calibration adjustments as needed. There are many qualified calibration service providers out there than can verify the accuracy and precision. This ensures that your pipettes remain in tip-top shape and continue to provide many hours of reliable use.

#6 Selection of Calibration Service Providers – They’re Not All the Same:

The selection of a calibration service provider is almost as important as purchasing a new pipette itself. A good calibration service provider will extend the life of your pipette and keep it accurate and precise. Adversely, selecting the incorrect calibration provider can be a crime against your pipette and shorten it’s lifespan. When selecting a pipette calibration provider, the following should be considered:

• Are they accredited to a calibration standard such as ISO 9001, ISO 17025, etc. If yes, ask for a copy of their calibration procedure (SOP’s) and accreditation certificate(s)
• Do they calibrate pipettes to manufacturer’s specifications, ISO 8655 tolerances, or customer tolerances?
• What are their calibration service offerings and pricing?
• Do they calibrate pipettes with manufacturer tips?
• Do they use manufacturer parts or manufacturer equivalent?
• What are their calibration lab temperature and humidity requirements?
• Do they verify pipettes gravimetrically or photometrically?
• What is the balance resolution used for the calibration of pipettes of different volume sizes?
• What is their current turn-around-time (TAT)?
• Do they provide onsite calibration service at the customer’s facility?
• Are they able to provide calibration service for most pipette models in the market?
• Can they provide training records of qualifications for different pipette models?
• Do they provide true preventive maintenance, replacement of parts, and calibration?

#7 Selecting the Incorrect Pipette for The Application Assay:

Another common crime committed against pipettes is asking the pipette to do an application assay that it is not designed to handle. There are three common pipette systems and selecting the correct one(s) is vital. These three pipette systems are:

• Air-Displacement: Air displacement pipettes are the most commonly used pipettes and can be found in almost every lab throughout the world. This style of pipette uses an internal piston assembly, seal, and o-ring to create a partial air vacuum inside of the white colored shaft. The partial air vacuum allows for the displacement of air that is needed for the aspiration and displacement of liquids.
  • Excels at: Aspirating and dispensing aqueous (water-like) liquids.
  • Does not excel with: More dense, viscous, volatile, high surface tension liquids.
  • Comments/Observations: If you find that the air-displacement pipette does not work as well with your liquids or application assay, consider the positive displacement pipette.
  • Examples: Eppendorf Research Plus, Gilson Pipetman, Rainin Pipet-Lite XLS, Finnpipette, Sartorius Tacta, etc.
• Positive Displacement (Pos-D): Positive Displacement pipettes are almost as common as air displacement pipettes. The Pos-D uses an external capillary and piston (CP) I order to aspirate and dispense viscous, volatile, aqueous, and high surface tension liquids. This style of pipette does not have an “internal air vacuum” as the external piston comes in direct contact with the liquid in order to aspirate and dispense t from the capillary.
  • Excels at: Aspirating and dispensing viscous, dense, volatile, high surface tension, and yes; aqueous (water-like) liquids.
  • Does not excel with: N/A, the accuracy and precision specifications of Pos-D pipettes are wider/larger than air displacement pipettes due to direct contact of liquid with the piston, friction, coefficient of expansion of the plastics in the capillary, etc.
  • Comments/Observations: While the Pos-D can be used with aqueous-like liquids, the cost of purchasing capillary and pistons (CP’s) is higher than the cost of polypropylene (PP) tips used for air displacement pipettes.  PP tips cost is ~10 -15 cents each, CP’s ~50-75 cents each.
  • Examples: Eppendorf Repeater X-Stream, Brand Handy-Step, Gilson Microman, RAININ Pos-D, etc.
• Serological: Serological pipettes are used for the transfer of large liquids from one container to another. These pipettes use an external, graduated plastic or glass tube that allows the user to aspirate and dispense liquids.
  • Excels at: Transferring aqueous-like and other liquids through an external glass/plastic graduated tip that attaches to the unit.
  • Does not excel with: N/A, serological pipettes are not calibrated instruments. The graduated plastic/glass tube is sold calibrated.
  • Comments/Observations:  Internal filters, tubing, and motor need to be checked time-to-time for liquid, debris and or replaced.
  • Examples: Pipet-Aid Filler, Eppendorf Easy-Pet, etc.

#8 Not Maximizing the Pipette Potential:

You can severely minimize damage to your pipettes by giving the following recommendations serious consideration:

• Perform proactive parts replacement with manufacturer parts or manufacturer equivalent
• Implement and demonstrate good pipetting practices
• Use manufacturer’s tips with that manufacturer’s brand of pipette (best accuracy and precision)
• Conduct routine pipette liquid inspection checks at least monthly
• Conduct routine calibration verification (every 6 – 12 months based on pipette model & volume size)

#9 Over Adjusting the Pipette

Adjusting the pipette over it’s intended maximum volume can cause potentially costly damage.

#10 Doing Nothing:

The biggest crime against pipettes is doing nothing at all. Pipettes are sometimes viewed as consumables that can be tossed and replaced. Having trusted resources that you can turn to when needed for advice, recommendations, or support is only a call or e-mail away. We are here to assist when you need us.

Phone: 817-483-9883 or Contact Us

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

The life span of pipette parts may vary based on the:

• Frequency of pipette use, and if used by multiple personnel
• Types of liquids aspirated and dispensed
• Storage conditions when not in use
• Frequency of preventive maintenance and calibration service

There are five (5) common pipette parts/components that attribute to ~95% of all performance issues. These five parts are:

• Seal and O-Ring
  • Roughly 60% of all pipette performance concerns are the direct result of a seal and/or o-ring failure
• Piston Assembly
  • Roughly 20% of all pipette performance concerns are the direct result of a rusted, pitted, chemical splash, bent/warped, or chipped piston
• Shaft
  • Roughly 10% of all pipette performance concerns are the direct result of a worn, chemical splash shaft that prevents tips to seal optimally
• Tip(s)
  • Tips can account for up to 5% of performance issues. This rate could be higher if tips are used from a manufacturer different than the pipette manufacturer.  Manufacturer’s design their pipettes to perform best with their tips. While other tip brands may be compatible, the end user should verify that the volume aspirated and dispensed is desirable. 

• Handle/Body
  • The remaining 5% of performance concerns are typically caused by a part inside the pipette body (i.e.: bent plunger rod, calibration screw, volume display, etc.).

Related Posts:

Top 10 Crimes Committed Against Pipettes

Frequency of Preventative Maintenance and Calibration

General Troubleshooting – Liquid Leak Check Testing & 12 Point Pipette Inspection

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

Most major manufacturers recommend pipette preventative maintenance (PM) and calibration service at least every 12 months, based on use. Twelve months is a good starting interval and should include:

• A liquid leak test, 12-point inspection
• Cleaning
• Manufacturer recommended pipette preventative maintenance
• Replacement of common PM parts, such as the seal
• lubrication of the piston assembly with manufacturer lubricant (as required by the manufacturer)
• And calibration adjustments, as needed. Calibration should be a last resort after all other components are deemed good.

Printable Calibration Log
Printable Calibration Stickers (for use with Avery 5960 labels)

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.

There are many different standard/universal pipette tips on the market that can be used and interchanged across different manufacturer’s pipettes. However, lower price and universal fit is not always the best logic when selecting tips for your pipettes.

Manufacturer-Made Tip Used With That Manufacturer’s Pipette

This pair provides the best results. The tips are specifically designed to load, seal, and deliver the desired volume of liquid accurately and precisely.

Universal Tips Used With A Different Manufacturer’s Pipettes

If mixing manufacturers, users can expect up to a 10% margin of error in the volume of liquid aspirated/dispensed. This is due to various factors, such as:

• Tip sealing
• Pore size of filtered tips
• Tip thickness
• Tip opening
• Flash
• Tip autoclaving

Note: If filtered pipette tips are used, the pore size (micron size of the holes in the filter that allow air to pass/permeate through) can affect the volume of liquid dispensed due to different pore sizes and materials used by different tip manufacturers). Air flow can begin to be restricted when the pore size is smaller than ~20uM (microns).

Disclaimer: Any action you take using the information on this website is strictly at your own risk. The information herein does not constitute professional advice and is general in nature. We make no warranty that this information will meet your requirements, be safe, accurate, or error-free. Pipette Supplies, Inc. is not responsible for any errors or omissions, any results obtained from the use of this information, or any loss or damage arising out of the use of this information. This site is for educational purposes only.
Fair Use: Copyright Disclaimer under section 107 of the Copyright Act of 1976, allows for “fair use” for purposes such as comments, criticism, teaching, scholarship, news reporting, and research.
Fair use is permitted by copyright statute that might otherwise be infringing.