These kits were designed to monitor kidney function by quantitative estimation of albumin in human urine. They successfully measure albumin concentrations well outside the range of conventional dip-stick methods.
To complete the assay, standard dilutions and urine samples are added to a plate precoated with human albumin. An enzyme conjugated anti-albumin antibody is added, and the plate is incubated for 30 minutes. During this time the conjugated antibody binds to either the albumin on the solid phase or to that in the liquid phase, hence the notion of competition. Thereafter, components remaining in the liquid phase are washed away, and bound conjugate determined using TMB Substrate Solution. The chromogenic reaction is stopped after 2-5 minutes using dilute acid (Albuwell). Color intensity is determined spectrophotometrically, with a microtiter plate reader (Albuwell).