Quantification of albumin in cerebrospinal fluid

A standard spectrophotometric method for the quantitation of urinary albumin using bromphenol blue is evaluated to determine whether this method could be used to quantify cerebrospinal fluid albumin. In the modified procedure, 200 microliters of sample is added to 3 ml of bromphenol blue solution and the absorbance is read spectrophotometrically at 610 nm. Using standards and controls, the results were compared with known values and found to be both precise and accurate. The bromphenol blue method was compared with an immunoturbidometric method and found to be more precise and accurate, easier to perform, and cost effective. When compared to other dye-binding methods the bromphenol blue method is unique in its extremely low linear range and limit of detection. A minor disadvantage was the increased sample size necessary to obtain the increased precision.