Figure 3From: A simple set of validation steps identifies and removes false results in a sandwich enzyme-linked immunosorbent assay caused by anti-animal IgG antibodies in plasma from arthritis patients Testing for false negative results and other matrix effects. (A) False negative measurements. OD signal from unspiked and spiked plasma samples from two arthritis patients in wells coated with anti-IL-24 specific antibody. (B) Identification and removal of false negative measurements. OD signal from unspiked and spiked plasma samples from the same two arthritis patients in wells coated with anti-IL-24 specific antibody after preincubating samples with a combination of mouse, goat, bovine and human immunoglobulins. (C) Spike recovery assessment in three other arthritis patients. Calculated IL-24 concentrations from unspiked patient samples and patient samples spiked with 800 pg/ml rh IL-24 in wells coated with anti-IL-24 specific antibody after preincubating samples with immunoglobulins. (D) Linearity-of-dilution assessment in three other arthritis patients. Calculated IL-24 concentrations in samples preincubated with immunoglobulin and diluted 4/6, 2/6 and 1/6 in wells coated with anti-IL-24 specific antibody.Back to article page