Saturation of Serum with CO 2 . A Simple Test for Hyperglobulinemia. ∗

Abstract

Ray 1 described the development of cloudiness or flocculation on dilution of the blood with distilled water in cases of kala-azar. Normal blood gives a clear solution on such dilution. An improvement of this test was introduced by Sia, 2 who used measured amounts of blood and distilled water and distinguished different degrees of reaction. The application of the water test in Bilharziasis was described by Salah. 3 The general applicability of this test in conditions of hyperproteinemia was pointed out by Bing. 4 A positive water test in Stiil's disease was described recently by Taussig. 5

The test is based on the flocculation of euglobulin, the least soluble globulin fraction. Generally it is positive within an hour in diseases associated with high globulin concentrations such as kala-azar, lymphogranuloma- inguinale, multiple myeloma, etc. However, if the concentration of globulin ranges between 3 and 4%, a positive test is obtained only after standing for a considerable time. In these cases the test can be rendered more sensitive and the reaction accelerated by saturating the diluted serum with carbon dioxide of low tension or alveolar air. The flocculating tendency is increased by the lowering of the pH toward the isoelectric point of globulin, pH 5.2. The actual acidity produced under various conditions of dilution and carbon dioxide saturation, as measured with the quinhydrone electrode is given in Table I. The figures of 6.12 and 5.95 are approximately in agreement with the pH of 5.8 reported by Doladihle and Morel 6 in 1:17 diluted serum after saturation with carbon dioxide gas.

Saturation of diluted serum with carbon dioxide precipitates the euglobulin more or less completely. Myttenaere and Bessemans 7 determined the total globulin in the serum by saturating the 1 :10 diluted serum with carbon dioxide. However, they give no figures to demonstrate the accuracy of this method. In 4 cases of multiple myeloma Jacdbson' found that the precipitate obtained by carbon dioxide saturation contained from 924% of total globulin.