The Mouse Anti-DNP IgM ELISA Kit is based on a solid phase enzyme-linked immunosorbent assay (ELISA). The assay uses DNP-BSA as the capture antigen (coated on the microtiter wells) and horseradish peroxidase (HRP) conjugated anti-mouse IgM antibodies for detection. Serum or plasma samples are diluted and incubated alongside standards in the microtiter wells for 45 minutes. The wells are subsequently washed, and HRP conjugate is added and incubated for 45 minutes. Anti-DNP IgM molecules are thus sandwiched between immobilized DNP and the detection antibody conjugate. The wells are then washed to remove unbound HRP-labeled antibodies, and TMB Reagent is added and incubated for 20 minutes at room temperature. This results in the development of a blue color. Color development is stopped by the addition of Stop Solution, changing the color to yellow, and optical density is measured spectrophotometrically at 450 nm. The concentration of anti-DNP IgM is proportional to the absorbance at 450 nm and is derived from a standard curve.