A

David

Darling

assay

An assay is the analysis of a substance or mixture to determine its constituents or their level. In metallurgy, it refers to the amount of metal present in a sample of material such as ores and alloys; the term is normally reserved for finding the proportion of gold, silver, or platinum present. In life sciences, it is also the estimation of strength of a drug or substance by comparing its effects in test animals to a reference standard.