1. MICROPIPETTE CALIBRATION- M. ASIF
Micropipettes Calibration
Micropipettes are precision instruments. As per international standard organizations (ISO 8655),
pipettes require routine inspection, cleansing, maintenance and calibration to ensure accuracy
and precision of dispensed volume. The accuracy and precision of pipette decides the quality of
test result performs in particular laboratory.
Direction regarding device requirements and test conditions Water Density Table
 For accurate calibration follow gravimetric method with
recommended balance types and resolution value as follow:
Volume range ( µl) Balance Type Readable resolution (mg)
1 - 10 Microscale 0.001
>10 - 100 Semi-Microscale 0.01
>100 - 1.000 Analytical Scale 0.1
 Use distilled or deionized water.
 Perform calibration in draught-free room at constant
temperature of water, pipette and air between 15°C to 30°C
(±0.5°C). The relative humidity must be above 50%.
 Place water, pipettes and tips in calibration room at least 2 hours before the start of
calibration to reach equilibrium with the test room conditions.
 A new tip should be pre-wetted 3 to 5 times to improve the accuracy.
 Always pipette water from a reservoir, do not take it back from the balance.
 Aspirate the volume to be tested slowly and evenly.
 Calibrate each pipette at the maximum volume and the minimum volume range.
 Do 10 pipettings with the minimum volume.
 Do 10 pipettings with the maximum volume.
 Always start the test with minimum volume first.
• Calculate accuracy and precision of both series.
• If the calculated results are within the limits specified by manufacturers acceptable error
limit, the pipette calibration is correct. If not, the pipette has to be adjusted and checked
again. If fail, place pipette out of service.
• Check calibration at least once a year.
Temperature (°C) Density (mg/uL)
15 0.999103
16 0.998946
17 0.998778
18 0.998599
19 0.998408
20 0.998207
21 0.997996
22 0.997774
23 0.997542
24 0.997300
25 0.997048
26 0.996787
30 0.995650

2. MICROPIPETTE CALIBRATION- M. ASIF
Evaluation of accuracy
The specified accuracy is the limit to the systematic error, which is the difference between the
mean volume of actual measurements and the true value of the volume set on the instrument. The
systematic error (E) can be estimated as follows:
E systematic error
V0 nominal volume
mean volume
The accuracy of a pipette can be expressed as a percentage of the nominal volume:
• Evaluation of precision
The specified precision is the limit to the random error, which is the distribution of the measured
values around a mean value. For pipettes, precision refers to a within-series group of data, and
therefore to repeatability. The random error is then quantified by the standard deviation of
measurements performed at a given volume setting under the same measuring conditions. The
standard deviation (SD or “s”) can be estimated as follows:
The precision of a pipette can also be expressed as a percentage of the mean volume. This is
known as relative standard deviation (RSD) or coefficient of variation (CV), and is estimated as
follows:

3. MICROPIPETTE CALIBRATION- M. ASIF
Maximum permissible errors according ISO 8655
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.

4. MICROPIPETTE CALIBRATION- M. ASIF
Micropipettes Calibration Worksheet
Pipette Code: ________________ Volume Capacity (μL): _____________ Manufacturer: ____________
Balance used: ________________ Thermometer used: _____________ H2O Temperature: ____________
Analyst: ________________ Check Date:
____________
Minimum Volume (μL) Maximum Volume (μL)
Nominal
Volume (μL)
Weight (mg)
Actual
Volume(μL)
Nominal
Volume (μL)
Weight (mg)
Actual
Volume(μL)
Water
Density
(mg/μL)
1
2
3
4
5
6
7
8
9
10
Average
Std. Deviation
Precision
Error (%)
Accuracy
Error (%)
Sr. No.
RESULTS
Pass
Fail
If fail , place pipette out of service