Further studies on the anti-immunoglobulin G hemagglutination-inhibition test for influenza.

Incorporating species-specific anti-immunoglobulin G (IgG) serum into the hemagglutination-inhibition (HI) test for influenza markedly increased sensitivity without loss of specificity. The effectiveness of anti-IgG serum for augmenting antibody titers may be influenced by the variable potency of commercial anti-IgG preparations. Maximal enhancement of HI titers was achieved when anti-IgG serum and virus-antiserum mixtures were incubated at 23 C for 10 min. Precision and reproducibility of the test were within acceptable limits. Other conditions likely to affect the test were investigated.