Which of the following questions correctly reflects a concept from the immunoassay content?

• A. EMIT is unrelated to immunoassays
• B. Only ELISA is a homogeneous immunoassay
• C. Immunoassays can be used to quantify vitamins, hormones, and drugs
• D. Immunoassays cannot quantify any clinical analytes

Answer: (C)

Immunoassays detect and quantify substances in a sample by using the specific binding between antibodies and their targets, and they are versatile enough to measure a wide range of clinically relevant analytes. This broad applicability—quantifying vitamins, hormones, and drugs—is what makes the statement correct. EMIT is a well-established immunoassay technique, so claiming it’s unrelated isn’t accurate. ELISA is a common format, but it’s not the only type, and many immunoassays are heterogeneous (involving a separation step) rather than purely homogeneous. Immunoassays are routinely used to quantify clinical analytes, so the notion that they cannot quantify anything is incorrect.