Overview
ISO/TR 6037:2024 provides a Technical Report for assessing the measurement uncertainty of volume delivery by automated liquid handling systems (ALHS). It adopts the ISO/IEC Guide 98-3 (GUM) approach and supports the measurement procedures described in ISO 23783-2. The report separates uncertainty into components associated with the measuring system, the device under test (ALHS), and the liquid delivery process and includes informative annexes for common volume measurement procedures.
Key topics and technical requirements
- GUM-based uncertainty workflow: defines the steps to model the measurand, estimate input quantities, calculate sensitivity coefficients, combine uncertainties, determine effective degrees of freedom and select a coverage factor k to obtain expanded uncertainty.
- Uncertainty component structure:
- Measuring system components (detailed per procedure in Annex A–C).
- ALHS-specific components (resolution, air cushion, system liquid effects, exchangeable tips, environmental and electrostatic effects).
- Liquid delivery process components (repeatability, reproducibility).
- Procedure-specific modelling: Annex A - dual‑dye ratiometric photometric; Annex B - gravimetric; Annex C - optical image analysis of droplets. Each annex gives guidance on estimating type A and type B uncertainties for that technique.
- Resolution uncertainty: includes an explicit expression for resolution-related standard uncertainty:
u(res) = Δres / √12 (where Δres is the volume selection resolution).
- Optional thermal corrections: guidance on uncertainty from cubic expansion coefficients and how thermal effects (including air cushions) can influence uncertainty estimates.
- Practical calculation elements: covariance consideration between inputs, combined standard uncertainty of the mean volume, sensitivity coefficients, coverage factor selection and reporting expanded uncertainty. Examples and sample calculations are provided in Clause 13.
Practical applications - who uses this standard
- Calibration laboratories validating and calibrating ALHS performance and issuing uncertainty budgets.
- Manufacturers and R&D teams designing, qualifying and documenting ALHS performance claims.
- Quality assurance and regulatory teams in clinical, pharmaceutical and biotech labs requiring traceable uncertainty statements for volumetric workflows.
- Lab managers and method validation specialists using uncertainty estimates to evaluate assay robustness, liquid transfer accuracy and transfer reproducibility.
- Typical applications: routine calibration of pipetting robots, verification of dispensed volumes for high-throughput screening, method development for assay volume control, and conformity assessment against ISO 23783 series.
Related standards
- ISO 23783-1 (vocabulary and general requirements)
- ISO 23783-2 (measurement procedures for ALHS)
- ISO/IEC Guide 98-3 (GUM - expression of uncertainty)
- ISO/IEC Guide 99 (VIM - metrology vocabulary)
Keywords: ISO TR 6037, automated liquid handling systems, measurement uncertainty, ALHS calibration, volume measurement, gravimetric, photometric, uncertainty budget, GUM.
