Pipette Calibration Terms & Definitions
Understanding Key Pipette Calibration Terms
Whether you're reviewing a calibration certificate, evaluating a service provider, or learning more about laboratory quality standards, understanding common calibration terminology can help you make more informed decisions.
This glossary defines key pipette calibration terms commonly referenced in ISO 8655, ISO/IEC 17025, calibration certificates, and laboratory quality programs.
Looking for answers to common calibration questions? Visit our Pipette Calibration FAQs page to learn about calibration intervals, ISO standards, measurement uncertainty, accreditation, and more.
A
Adjustment
Definition:
The process of setting or modifying a pipette to achieve the desired metrological performance.
Adjustment may improve pipette performance when measurement results fall outside acceptable limits. Adjustment is different from calibration, which evaluates performance rather than changing it.
C
Calibration
Definition:
A series of operations used to establish the relationship between the volume dispensed by a pipette and its intended or selected volume.
Calibration verifies whether a pipette is delivering accurate and repeatable measurements. Regular calibration helps support data integrity, quality assurance, and regulatory compliance.
Calibration Certificate
Definition:
A document that reports the results of a calibration.
Calibration certificates provide documented evidence of instrument performance and may include calibration data, measurement uncertainty, traceability information, and environmental conditions.
Certificate of Conformity
Definition:
A document stating that a device satisfies specified requirements or standards.
Certificates of conformity help demonstrate compliance with established performance requirements or quality standards.
Conformity Testing
Definition:
A systematic examination used to determine whether specified metrological requirements have been met.
Conformity testing helps determine whether a pipette performs within established acceptance criteria.
D
Dead Air Volume
Definition:
The volume of air located between the lower part of the piston and the liquid surface in an air displacement pipette.
Changes in dead air volume can affect measurement accuracy and are one reason environmental conditions influence pipette performance.
Dead Liquid Volume
Definition:
For positive displacement pipettes, dispensers, diluters, and burettes, the amount of liquid that remains within the cylinder but is not part of the dispensed volume.
Dead liquid volume can influence measurement performance and repeatability, particularly in precision liquid handling applications.
M
Maximum Permissible Error (MPE)
Definition:
The upper or lower allowable limit for deviation between the dispensed volume and the selected or nominal volume.
Maximum permissible errors establish the performance limits a pipette must meet to comply with ISO 8655 requirements. These limits help laboratories evaluate pipette accuracy and precision. Learn more: What Are Maximum Permissible Errors?
Measurement Uncertainty
Definition:
A parameter associated with a measurement result that characterizes the range of values that could reasonably be attributed to the measurement.
Measurement uncertainty helps quantify confidence in calibration results. The lower the uncertainty, the greater the confidence in the reported measurement. Related resource: ISO 8655 Procedures
N
Nominal Volume
Definition:
The volume specified by a pipette manufacturer and used to identify the instrument's measuring range.
Nominal volume serves as the reference point for evaluating a pipette's performance and calibration results.
R
Random Error
Definition:
The variation among multiple measurement results around the calculated mean.
Random error is used to assess pipette precision. Lower random error generally indicates more consistent measurement performance.
S
Supplier's Declaration
Definition:
A written statement from the supplier confirming that a device conforms to specified requirements.
Supplier declarations may be used to communicate compliance with applicable standards and performance specifications.
Systematic Error
Definition:
The recurring difference between a pipette's dispensed volume and its selected volume.
Systematic error is used to evaluate pipette accuracy. A consistent bias in measurement results may indicate that adjustment, maintenance, or repair is required.
U
Uncertainty of Measurement
Definition:
The calculated range within which the true measurement value is expected to exist.
Measurement uncertainty is a critical element of accredited calibration programs and plays an important role in calibration decision-making, risk assessment, and compliance.
Useful Volume Range
Definition:
The portion of a pipette's volume range that can be used while remaining within specified maximum permissible errors.
The useful volume range helps users understand where a pipette is capable of producing accurate and compliant measurements.
User Adjustment
Definition:
An adjustment performed using mechanisms provided to the user by the manufacturer.
Some pipettes permit user adjustment within manufacturer guidelines. Laboratories should ensure any adjustment activities align with internal quality procedures and calibration requirements.
