An automated estimation of serum globulins.

UTOMATIC ESTIMATION of serum globulins in human serum is normally measured as the difference between the total protein and the albumin as estimated by the dye binding capacity of the albumin, usually using 2-(4’hydroxyazobenzene) (HABA). However, it has been shown that a variety of drugs will upset dye uptake by the albumin (1). In addition, the absorbance of the native serum is so high, and the wavelength of maximum absorption of the bound HABA dye so close to that of serum, that it is necessary to run blanks on all samples estimated. Glenn (2) showed that serum globulins could be estimated automatically by the precipitation of the globulins of the serum proteins by a 27.4% (w/v) sodium sulphate solution and that the resultant turbidity bore a direct relationship to the globulin present in the serum. This method was modified by Jones (3) so that it was suitable for use with a 15 mm flowcefl. In our experience, however, we have found that the sodium sulphate solution must be kept warm in order to prevent crystallization during the estimations, and further, that the globulin precipitate tends to form in large unequal particles and hence causes an irregular response by the recorder. In addition, the base line tends to rise continually throughout a series of estimations due to precipitation of the globulins on the walls of the flowcell. In the method to be described, using an AutoAnalyzer system, globulins are flocculated by a sodium sulphate-sodium suiphite mixture which remains in solution at lower temperatures, and initially results