ASSAY definition: to examine or analyze. See examples of assay used in a sentence. An assay is a laboratory procedure that identifies or measures a specific substance in a sample. Whether it’s checking how much of a drug is in a tablet, detecting bacteria on a kitchen surface, or measuring hormone levels in your blood, the underlying process is an assay. The word “assay” and “test” are often used interchangeably in medical and scientific settings, but an assay is. Assay An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity. assay (plural assayes) Examining; investigation, looking into, research: Trialling, assaying; the ensuring of quality (usually of a substance, but also of a document) The trial or testing of one's personality or personal qualities. An attack (as a trial of one's mettle or ability on the battlefield) The trialling of comestibles or nourishments (mostly in ceremony) A try or effort towards. The meaning of ASSAY is to analyze (something, such as an ore) for one or more specific components. How to use assay in a sentence. Did you know? CH50 assay a test of total complement activity as the capacity of serum to lyse a standard preparation of sheep red blood cells coated with antisheep erythrocyte antibody. The reciprocal of the dilution of serum that lyses 50 per cent of the erythrocytes is the whole complement titer in CH50 units per milliliter of serum. An assay is a breakdown of a material, examining the individual parts that make up the whole. When you assay a situation, you look at all the elements that created the problem in order to come up with a solution. ASSAY definition: 1. to examine a substance to find out how pure it is or what its properties (= qualities) are: 2…. Learn more. Define assay. assay synonyms, assay pronunciation, assay translation, English dictionary definition of assay. an analysis of a substance, esp. of an ore or drug: His find required an assay to determine its value. Not to be confused with: essay – try; subject to a. An assay is a laboratory procedure or test that is performed to determine the presence, concentration, quality, or biological activity of a specific substance or component within a sample.