What does an enzyme-linked immunosorbent assay (ELISA) test do?

An enzyme-linked immunosorbent assay (ELISA) test is a powerful technique used primarily to detect and quantify substances such as proteins, antibodies, and hormones in a liquid sample. The key aspect of ELISA involves the use of antibodies that specifically bind to the target substance. When the target is present in the sample, the antibody will bind to it, and this binding can lead to a color change facilitated by an enzyme linked to the antibody. The intensity of this color change is proportional to the amount of the target substance in the sample, allowing for quantification.

This method is widely used in clinical laboratories for diagnostics, such as measuring the levels of HIV antibodies or checking for allergens in food items. The unique feature of using antibodies means that the test is highly selective, reducing the chance of false positives compared to other methods. Other options mentioned, such as measuring enzyme concentration, testing for genetic mutations, or determining pH levels, do not encapsulate the fundamental principle of ELISA, which revolves around antibody-antigen interactions and their subsequent detection through enzymatic reactions leading to observable changes, typically color changes.