Which type of immunological test is primarily used to detect whole antigens in a sample?

• A. PCR (Polymerase Chain Reaction)
• B. ELISA (Enzyme-Linked Immunosorbent Assay)
• C. Western blot
• D. Agglutination test

Answer: (D)

Verified step by step guidance

1. Understand the purpose of each immunological test listed: PCR detects genetic material (DNA or RNA), ELISA detects specific proteins or antibodies, Western blot identifies specific proteins after separation by electrophoresis, and Agglutination tests detect whole antigens or cells by visible clumping.
2. Recall that PCR is a molecular technique used to amplify DNA sequences, so it is not primarily used to detect whole antigens but rather nucleic acids.
3. Recognize that ELISA is designed to detect and quantify soluble antigens or antibodies, often in a purified or processed form, rather than whole cells or particulate antigens.
4. Know that Western blot is used to detect specific proteins separated by gel electrophoresis, which involves denatured proteins rather than whole antigens in their native form.
5. Identify that Agglutination tests involve the clumping of particles (such as cells or latex beads) coated with antibodies or antigens, making it the primary method to detect whole antigens in a sample through visible aggregation.