Which tests detect antigens/antibodies?

• A. ELISA, agglutination
• B. FISH, CISH, IHC, ICC, Flow cytometry
• C. PCR, RT-PCR
• D. SALL4, LIN26

Answer: (B)

Antigen/antibody detection relies on binding between a specific antibody and its target protein, with a visible signal showing where or how much of that target is present. The key methods that do this directly are immunohistochemistry and immunocytochemistry, which use labeled antibodies to visualize a protein’s presence and location in tissue sections or individual cells. Flow cytometry also fits this idea, using fluorescently labeled antibodies to detect and quantify particular antigens on or inside cells, enabling analysis of large cell populations.

FISH and CISH, by contrast, detect nucleic acids (DNA or RNA) with complementary probes, not proteins, so they aren’t about antigen/antibody detection. PCR and RT-PCR likewise target genetic material rather than proteins. SALL4 and LIN26 are protein markers often identified by antibody-based methods, but they’re markers rather than standalone antibody-detection techniques.

So the set that best represents tests detecting antigens/antibodies centers on immunodetection methods like IHC, ICC, and flow cytometry.