Colorimetric quantitation of albumin in microliter volumes of serum

Various non-immunochemical approaches to the quantitation of albumin in serum are reviewed. Salt fractionation techniques are unreliable, with substantial errors in estimating hypoalbuminemic states. Electrophoresis displays biases owing to irregular dye-binding or to densitometric scanning of irregular globulin bands. Currently, the most reliable colorimetric procedure for albumin quantitation is the rapid reaction with bromcresol green. By measuring final absorbance within fifteen seconds of mixing serum with reagent, the interference of globulins is eliminated. A microscale (5 microliter serum) rapid reaction for albumin assay has been developed; it can be readily automated on kinetic or centrifugal analyzers.