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Pipette Calibration - Guidelines
Guideline Number
Equ13-20-G
Effective Date
3-Sept-07
Page
1 of 6
Pipette Calibration Guidelines
Supersedes
New
Review by
Review date
1-Mar-13
Pipette Calibration
Subject
Peggy Coulter
Audit:
Questions pertaining to pipette calibration can be found in:

Equipment Section
CAP Accreditation Checklist:
Questions pertaining to the calibration of micro pipettes can be found in:

Chemistry and Toxicology Checklist section:

Hematology and Coagulation Checklist section:

Limited Service Laboratory Checklist section:

Microbiology Checklist section:
Background Information:
Micropipettes are precision laboratory instruments. They require routine maintenance and
calibration to ensure accuracy and precision. This is determined using gravimetric methodology
by using an analytical balance and weighing the amount of water delivered by the pipette. For
the purpose of calibration, milligrams and milliliters are considered to be equivalent. Calculation
of percent duplication and percent delivery is used to determine the precision and accuracy of
the pipette. Tolerance limits for pipettes are usually established by referring to the
manufacturer’s guidelines although some general guidelines are available if manufacturer’s
ranges cannot be obtained.
Resources
1. Clinical and Laboratory Standards Institute (CLSI) HIS-A2. A quality system model for
healthcare; approved guideline – second edition.
2. Johns Hopkins Hospital Clinical Laboratory Procedure Manual (1995). Eppendorf Pipette
Calibration
3. Operating Instructions for Eppendorf Pipette. (ND). Brinkman Instruments Inc. N.Y.
4. Westgard, J.O., PhD. (2002). Basic QC Practices: 2nd Edition. Westgard QC Inc.
Madison, WI.
Pipette Calibration
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Pipette Calibration - Policy
Pipette Calibration Policy
Approval Signature: Laboratory Director
Policy
Policy Number
Equ13-20-P
Effective Date
3-Sept-07
Last Review
27 July 2010
The laboratory has processes and procedures to effectively ensure that
pipettes are calibrated frequently to confirm their accuracy and precision.
The exact policy for calibration frequency will vary according to the
requirement of specific accrediting agencies.
For NIH Division of AIDS (DAIDS) the requirements are that pipettes should
be calibrated four times per year and that at least two of the calibrations
should be performed externally.
Purpose
This policy provides direction for the processes and procedures to
effectively ensure that all procedures performed using micropipettes meet
the established standards for precision and accuracy.
Responsibility
The Director (or his/her designee) of the Laboratory Program, the
Laboratory QA Program Manager and the International Laboratory Program
Manager have the authority to establish this procedure.
The Principle Investigator/Laboratory Manager is responsible for the
implementation of this procedure and for ensuring that all appropriate
personnel are trained.
All technologist and technicians working on clinical trial studies are
responsible for reading and understanding this SOP prior to performing the
procedures described.
Additional Information
as required
NA
Supporting
Documents
NA
Pipette Calibration
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Pipette Calibration - Process
Pipette Calibration Process
Policy Number
Equ13-20-Pro
Effective Date
3-Sept-07
Last Review
27 July 2010
Supersedes
New
Approval Signature: Laboratory Director
Process for Pipette Calibration
Who’s Responsible
Instructions

Staff Technologist

Department Supervisors
Pipette Cleaning and
Maintenance SOP

QA Technologist

Lead Technologist

QA Technologist

Department Supervisors
What Happens
Micro Pipettes require
cleaning and maintenance
Micro Pipettes require
quarterly calibration
Micro Pipette Calibration
results are reviewed
Pipette Calibration
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Pipette Calibration SOP
Pipette Calibration SOP
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Pipette Calibration - SOP
Author(s), Name &
Title
Mark Swartz MT(ASCP)
Document
Number
Effective
Date
International QA/QC Coordinator
Equ13-20-SOP
3 Sept-07
Name, Title
Signature
Date
Name, Title
Signature
Date
Approved
By
SOP
Annual
Review
Version # [0.0]
Revision Date
[dd/mm/yy]
Description (notes)
Revision
History
Name (or location)
# of copies
Name (or location)
# of copies
Distributed
Copies to
Associated Forms:
Pipette Calibration
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I acknowledge that I have read, understand and agree to follow this SOP.
Electronic Signature
Pipette Calibration
Version #
Version#: 1.0
Date
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Purpose:
Micropipettes are precision laboratory instruments. They require routine maintenance and
calibration to ensure accuracy and precision. This procedure establishes standards for pipette
calibration to ensure they perform with acceptable accuracy and precision.
Frequency:

Before pipettes are newly placed into service

Periodically; suggested interval is quarterly or according to manufacturer guidelines

After cleaning

Anytime a pipette becomes dismantled and repaired

As a means of troubleshooting assay problems
Supplies:

Micropipettes for calibration

Analytical balance with maintenance completed

Pipette tips for appropriate pipette volumes

Weigh boats

Worksheet for Micropipette Calibration

Reagent grade, room temperature water in a clean glass beaker

Thermometer

Calculator

Peanut Oil (Optional)
Procedure:
A. Pipettes 5-100 ul
1. Record ambient room temperature to determine water density to be used in
calculations.
2. Place a plastic weigh boat and pipette tip on the balance and tare the balance.
3. Place the tip onto the pipette requiring calibration. Pipette room temperature
reagent grade water into the tip using good pipetting technique.
4. Turn the pipette in a horizontal position and remove the tip taking care not to lose
any of the water.
5. Weigh the tip and water on the same plastic weigh boat and record the result.
6. Repeat steps again to obtain a second result.
B. Pipettes 100 – 1000 ul
1. Record ambient room temperature to determine water density to be used in
calculations.
Pipette Calibration
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2. Place a plastic weigh boat on the balance and tare the balance.
3. Pipette room temperature reagent grade water into the tip using good pipetting
technique.
4. Dispense the reagent grade water onto the weigh boat.
5. Allow the balance to equilibrate and record the reading.
6. Repeat steps again to obtain a second result.
Procedural Notes:

Avoid handling pipette tips with your fingers. Use a lint free wipe or forceps whenever
possible.

Two readings are required. Two fresh pipette tips must be used to confirm accuracy.

Peanut Oil can be used to prevent evaporation of water. Simply place a small amount of
the oil in the weigh boat in procedural step 2 (A or B).

One weigh boat may be used for multiple readings with a tare performed between each
weight measurement. Multiple pipette calibrations will require the boat to be emptied
and re-zeroed. Reminder: The balance will not allow the tare of a negative reading. The
balance must be re-zeroed.
Calculations:
Density of Water: at 20ºC = 0.998
at 25ºC = 0.997
at 30ºC = 0.996
Precision:
To check duplicates:
weight 1 – weight 2 = ∆ weight
weight 1 + weight 2 = x̄ weight
2
∆ weight = % difference
x̄ weight
Sample Calculation:
0.3006 - 0.3010 = -0.0004
0.3006 + 0.3010 = 0.3008
2
-.0004 X 100 = -0.13%
0.3008
Accuracy:
x̄ weight x 100
= % Delivery
(Pipette volume (mL)) x density of water
Pipette Calibration
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Sample Calculation:
.3008 x 100 = 100.6%
.300 x .997
(density of water at 25ºC)
Expected Results:
Acceptable accuracy and precision ranges for pipettes should be based on manufacturers guidelines
stated in the pipette package insert. Accuracy and precision ranges of plus or minus 4% for pipettes 5-50
ul and plus or minus 2% for pipettes 51-1000 ul are a good guideline
Interpretation of Results:
1. Pipettes not meeting the established acceptance criteria for accuracy or precision should receive
routine maintenance before being calibrated again.
2. If a pipette cannot meet the acceptance criteria it should be removed from service until it can be
serviced by the manufacturer or an approved vendor.
3. Pipettes that do meet the established acceptance ranges should be labeled with a sticker that
records the actual accuracy of the pipette, the date of calibration and the initials.
References:
1. Clinical Laboratory Standards Institute (CLSI). Clinical Laboratory Technical Procedure Manuals;
Fourth Edition. CLSI Document GP2-A4 (ISBN 1-56238-458-9). Clinical and Laboratory
Standards Institute, Wayne, PA
2. Clinical and Laboratory Standards Institute (CLSI) HIS-A2. A quality system model for healthcare;
approved guideline – second edition.
3. Johns Hopkins Hospital Clinical Laboratory Procedure Manual (1995). Eppendorf Pipette
Calibration
4. Operating Instructions for Eppendorf Pipette. (ND). Brinkman Instruments Inc. N.Y.
5. Westgard, J.O., PhD. (2002). Basic QC Practices: 2 nd Edition. Westgard QC Inc. Madison, WI.
Associated SOP:
Analytical Balance Operation and Maintenance SOP and Appendices
Appendices:
Appendix A: Pipette Calibration worksheet
Appendix B: (Suggested): Appropriate pipette package inserts
Pipette Calibration
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