All of the following immunoassay testing techniques are paired with their correct characteristics except which of these answers?

• A. Fluorescent antibody test – microscopy.
• B. ELISA – radioactive label.
• C. Western blot – gel electrophoresis.
• D. All of the above are matched correctly.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the principle behind each immunoassay technique mentioned. The Fluorescent Antibody Test uses fluorescent dyes to label antibodies, which are then visualized under a fluorescence microscope, so it is correctly paired with microscopy.
2. Step 2: Review the ELISA (Enzyme-Linked Immunosorbent Assay) technique. ELISA uses an enzyme-linked antibody or antigen to produce a color change, not a radioactive label. Radioactive labels are characteristic of radioimmunoassays (RIA), so this pairing is incorrect.
3. Step 3: Examine the Western blot technique. Western blot involves separating proteins by gel electrophoresis, transferring them to a membrane, and detecting specific proteins with labeled antibodies, so it is correctly paired with gel electrophoresis.
4. Step 4: Compare all options to identify which pairing is incorrect. Since ELISA does not use radioactive labels, the statement 'ELISA – radioactive label' is the incorrect match.
5. Step 5: Conclude that the correct answer to the question is the ELISA paired with radioactive label, as it is the only mismatched pair among the options.