Fig 2. Correlations between the HI assay, ELISA-MNT, and NA-MNT for the measurements of anti-H5N1 antibodies.

Antibodies were measured in 40 serum samples from healthy volunteers immunized with two doses of inactivated H5N1 influenza vaccine and compared between the (A) HI assay and ELISA-MNT (B) NA-MNT and HI assay, and (C) NA-MNT and ELISA-MNT. Linear regression equations and correlation coefficients were calculated by linear regression analysis of the log transformed data.