Purpose: to compute a tier-like score for anti-HIV-1 sera (using ID50 titers) or antibodies (using IC50 titers).
Logistic regression is used to compute a tier-like neutralization potency (NP) value, which indicates the virus tier that a serum (or antibody) can be expected to neutralize. An associated p-value gives the false-positive probability from rejecting the null hypothesis of no slope in the inferred logistic curve. An NP value with a p-value above some predetermined cutoff (e.g., 0.1 or 0.2) should be considered unreliable. This analysis requires that your neutralization assays include HIV viruses (Envs) that have previously been analyzed. For details, please read Neutralization Index Explanation.