Comparison of Jenner-Kay and Bodansky Methods for Determining Phosphatase in Plasma and Serum. ∗

Abstract

Since the autumn of 1932 we have made phosphatase determinations in several hundred samples of plasma from cows'blood by the clinical method of Jenner and Kay 1 . This method as well as that of Kay 2 , of which it is a modification, has been criticized by Bodansky 3 ,⁴, because of unnecessarily large experimental errors; the method developed by Bodansky 3 ,⁴ is more rapid and is believed by him to eliminate the errors inherent in the Kay and Jenner-Kay technics.

Before we began to employ the Jenner-Kay method in the routine analysis of bovine plasma we had satisfied ourselves that sufficiently uniform results could be secured when it was applied to the type of plasma samples employed by us for other plasma analyses, namely, total calcium and inorganic phosphorus. These samples are a composite of equal parts of plasma centrifuged at once from citrated blood obtained on 3 successive days. Preliminary data obtained by the Jenner-Kay method from normal heifers whose plasma showed widely different levels of phosphatase showed for example that samples containing 31.46, 36.16 and 36.92 units per 100 cc. on successive days showed 34.70 units in the 3-day composite against a calculated value of 34.85 units. The same composite sample analyzed 38.72 units phosphatase after 6 days'storage. Another animal with plasma phosphate values of 16,50, 16.28 and 16.76 units per 100 cc. on successive days showed 16.70 units for the composite against 16.51 units calculated from the individual samples. A third animal with plasma phosphatase of 6.18, 6.98 and 6.96 units per 100 cc. on successive days showed 7.84 units in the composite against a calculated value of 6.71. These data, which were subsequently verified by a very large amount of data which will not be reported at this time, suggest that the phosphatase content of the blood plasma in dairy cattle is to a considerable extent an individual characteristic. Furthermore, it seemed apparent that the Jenner-Kay technic is applicable to the determination of plasma phosphatase in composite samples within reasonable limits of accuracy. The results also suggest that greater errors may be expected when the phosphatase content is low and that some inaccuracy may result if the composite sample is not analyzed promptly.