Using albumin to increase the sensitivity of the indirect antiglobulin test, which statement is true?

• A. It decreases sensitivity
• B. It increases sensitivity
• C. It does not affect sensitivity
• D. It inhibits reaction

Answer: (B)

Albumin acts as an enhancement medium in the indirect antiglobulin test to boost sensitivity. In this assay, IgG antibodies on red cells may be present at low density or have lower affinity, making agglutination hard to detect. Albumin creates a protein-rich environment that helps bring red cells closer together and reduces electrostatic repulsion between them, allowing antibodies to bridge adjacent cells more effectively. This increases the likelihood that the antiglobulin reagent will detect antibody-coated cells, yielding visible agglutination even for weaker or low-titer antibodies. So, using albumin specifically improves the test’s ability to detect antibodies, rather than decreasing or leaving unchanged the sensitivity, or inhibiting the reaction.