Quantitative measurement of blood pigments in cerebrospinal fluid by derivative spectrophotometry.

A spectrophotometric method for the simultaneous calculation of the concentrations of oxyhaemoglobin, methaemoglobin and bilirubin in cerebrospinal fluid is described, based on the first and second derivative spectrum between 350 and 650 nm. Specificity compares favourably with other methods currently in use. The proposed method minimises the effect of turbidity and permits the measurement of concentrations below 0.3 mumol/L.