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Professional Technical IVT

Competitive Binding Assay

An immunoassay technique where labeled and unlabeled hormones compete for binding sites on specific antibodies.

Full Definition

A competitive binding assay is a laboratory technique used in hormone testing where both the hormone being measured and a labeled version of the same hormone compete for limited binding sites on specific antibodies. The amount of labeled hormone that binds is inversely proportional to the concentration of the unlabeled hormone in the sample. This method is particularly useful for measuring small molecules like steroid hormones and thyroid hormones. The technique requires careful optimization of antibody concentration and incubation conditions to ensure accurate results.

Usage

Usage note: Capitalize when referring to a specific methodology or protocol name.

In Context

  • "The laboratory switched to a competitive binding assay for cortisol measurement due to improved specificity." — Laboratory protocol document
  • "Competitive binding assays are preferred for steroid hormone analysis because of their small molecular size." — Technical training manual

Also known as

competitive immunoassay competitive RIA

Contrasted with

sandwich assay non-competitive assay

Don't confuse with

sandwich immunoassay direct binding assay

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