assay: a standalone construct

In pharmacology a biological assay, or bioassay, estimates the potency or toxicity of a substance from the response it produces in living material rather than from its chemical make-up, which matters when a drug or toxin cannot be measured directly. Potency is read off a dose-response relationship, often summarised by a dose that produces a defined effect in half the subjects, such as the median lethal dose. Trevan's 1927 The error of determination of toxicity established the statistical treatment of such graded and quantal responses and gave the field its characteristic measure. The referent is a biological estimate of potency obtained through a response, a different construct from the metal content of an ore or the purity of a reagent.[1]

Unit

Relative potency or an effective/lethal dose (e.g. ED50, LD50) with confidence limits

Recovery means

Not applicable

Measured by

Estimated from dose-response curves using probit or logit models, comparing a test preparation against a reference standard