X-Ray Spectroscopy in the Clinical Laboratory

Abstract

Abstract Sulfur analysis in serum is performed with the X-ray spectrometer. The total sulfur content of normal serum in healthy adults is found to be 98 mg./100 ml. of serum ± 2.0 (2σ). This calculates to 1.44 gm. sulfur per 100 gm. of serum proteins ± 0.1 (2σ). The distribution of sulfur in the paper electrophoretic fractions was assayed by performing the electrophoresis and passing the unstained paper through the X-ray field at a constant velocity; 69.3 per cent of the total serum sulfur is found in the albumin fraction. The other fractions contain, for alpha1, alpha2, beta, and gamma globulins, 4.2, 9.5, 9.5, and 7.5 per cent, respectively, as mean values for the 16 healthy adults. From the protein content of each fraction, determined by staining, the gm. of sulfur per 100 gm. protein is calculated for each fraction as follows: Albumin, 1.74; A,, 1.61; A2, 1.37; beta, 1.09; and gamma, 0.67. The distribution of sulfur in the paper electrophoretic fractions from the two sera containing an abnormal fraction migrating with the gamma globulins was studied. The abnormal protein sulfur was low in these patients—only 0.18 and 0.16 gm. sulfur per 100 gm. of protein being found—as compared to 0.67 per cent in the normal. Both these sera came from patients with multiple myeloma. In the serum of 2 patients, which had abnormal globulins traveling with the beta globulins, one contained level of sulfur elevated to 1.42 gm./100 gm. protein, as compared with 1.09 for normal beta globulin. The diagnosis in this case was multiple myeloma. In the second case the sulfur content was low-0.43 gm. sulfur per 100 gm. protein. In this case the diagnosis in the patient was equivocal. Technics are described for determining the sulfur content of the different electrophoretic fractions with the X-ray spectrometer.