Uncertainties in SENAITE: what your results actually mean

An analytical result is never a point. It’s a point with a window around it. That window, the measurement uncertainty, is what regulators, accreditors, and any careful reviewer actually look at. SENAITE treats it as first-class data.

What SENAITE stores

Uncertainties live on the Analysis Service, on the Uncertainties tab. Each entry pairs a result range with a tolerance. A typical setup:

• 0 to 2: ±0.1
• 2 to 10: ±0.5
• 10 to 100: ±2

The upper bound is inclusive. A result of 2 picks up ±0.1. Values can be absolute (in the same unit as the result) or a percentage (2% of the value). Percentages are useful for services whose uncertainty scales with concentration.

What shows up in the report

When a technician enters a result, SENAITE resolves the matching uncertainty band and stores it with the result. Both are printed in reports and returned through the JSON API. Downstream tools (control charts, external LIMS, regulator submissions) receive the pair.

Where it changes decisions

Specifications define whether a result is in-spec or out-of-spec. Uncertainty widens both edges. A result of 10.4 mg/L with ±0.5 and a spec limit of 10 is not automatically out of spec. It sits in the shoulder. SENAITE surfaces the shoulder state so the verifier applies the lab’s policy consciously instead of missing an edge case.

Two things to get right

Bands should reflect real method performance. Copying ranges from a supplier data sheet is a start, not the answer. Update them from your own QC data periodically.

Absolute versus percentage matters. Below the LOQ, absolute uncertainties usually win. Above it, percentages often describe the method better. Mixing both across ranges is fine, and SENAITE supports it directly.

Uncertainty isn’t paperwork. It’s the difference between a report a lab can defend and one that quietly collapses in an audit.