Notes from the discovery benchAssays, instruments & drug discovery
AN·01Assay note · Assay quality

A better Z′ can hide a worse measurement.

When bright controls look unusually consistent, detector compression may be improving the statistic while distorting the result. Here’s how to tell.

Andrew Stewart8 min read2 figures · 1 checklist
Fig. 1 — Same plate, two gain settings
Gain in linear rangeProportional
Gain near saturationCompressed
Low controlHigh controlRelative signal →
Illustrative distributions, not measured wells. They show how compression can narrow a bright control. Whether changing gain produces this behavior depends on the reader; no universal gain or saturation threshold is implied.
BTBench tip

Read the plate map before you read the statistic

A spatial view can reveal patterns that one summary statistic hides. Start with the raw wells, then investigate the pattern.

A practical starting point
ANAssay note

When reading longer stops helping

Longer luminescence reads help when photon collection limits precision, but they cannot remove persistent differences between wells. This article shows how to compare repeated reads with independently prepared replicates, account for background noise, and choose a useful stopping point.

ANAssay note

A better Z′ can hide a worse measurement

A higher Z′ can reflect nonlinear detector compression rather than a better assay. This article explains how bright-well variation can shrink while effect sizes become distorted, and how to check proportionality without confusing detector behavior with assay chemistry.

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Consulting · looking ahead

Assay troubleshooting, detection strategy and instrument selection. For now, we’re sharing the knowledge through this library.

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