In serology, an antigen excess leading to false-negative results is known as which phenomenon?

In serology, an antigen excess leading to false-negative results is known as which phenomenon?

• A. Postzone effect
• B. Prozone effect
• C. Both
• D. Neither

Answer: (A)

In serology, tests rely on antigen-antibody lattice formation to give a visible result. When antigen is in excess, each antibody binds to separate antigen molecules and cannot cross-link multiple particles. This prevents lattice formation, so the test appears negative even though antibodies are present. This is known as the postzone phenomenon. The opposing situation, antibody excess, causes the prozone effect, also leading to a false negative under different conditions. Since the scenario specifies antigen excess, the postzone effect is the best term to describe it.

In serology, tests rely on antigen-antibody lattice formation to give a visible result. When antigen is in excess, each antibody binds to separate antigen molecules and cannot cross-link multiple particles. This prevents lattice formation, so the test appears negative even though antibodies are present. This is known as the postzone phenomenon. The opposing situation, antibody excess, causes the prozone effect, also leading to a false negative under different conditions. Since the scenario specifies antigen excess, the postzone effect is the best term to describe it.