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Current assay methods do not define the absolute concentrations of calcitonin in plasma of normal man. In our experience, the concentration was

An immunologic method of assay of HCG in serum has been developed using the hemagglutination inhibition reaction. Serum was treated with acetone and the HCG containing fraction was washed with absolute alcohol and ether. Immunologic assay of HCG in serum of 311 normal pregnant women revealed results comparable with those obtained by the various biological methods of assay both in the shape of the normal curve and in the actual concentration of the hormone measured in international units. In addition, the concentration of HCG in serum as compared with morning urine, both being assayed immunologically, has been found to be very similar. Finally, the rate of disappearance of the hormone from the serum as well as its presence in amniotic fluid in significant amounts has been determined.

A brief description of our experience with the immunoassay of insulin by the technic of Hales and Randle is given. Insulin values determined in twelve normal children and in seven cases of untreated diabetes mellitus in the fasting state and following a glucose load are presented. A newly diagnosed untreated child with diabetes mellitus had a low fasting insulin and gave very little response to test meal of glucose. Implications of these findings are discussed briefly.

The relation between functional antihemophilic factor (AHF) activity and AHF-like antigen was studied in the plasma of 25 known carriers of hemophilia. In 23 cases, this relationship was significantly different from that in normal women, at the 99% limit of confidence. In contrast, among families in which only one case of hemophilia had occurred, only five of nine mothers could be identified as carriers. This observation suggests that in some instances the hemophilia arose from a newly mutant gene. The data are consistent with the hypothesis that the proportion of antigen to AHF activity in carriers is determined by random activation or inactivation of the X chromosome.

Quantitative immunologic assay of the plasma of the proposita in a family with hereditary prothrombin deficiency demonstrated the defect to be due to an actual deficiency of the prothrombi...

Assays of urinary human chorionic gonadotropin (HCG) in normal and abnormal pregnancies performed by a hemagglutination inhibition method are presented. Antisera were produced in rabbits. An HCG preparation of pooled urine of pregnant women was used as a laboratory standard. 1st morning urine samples were obtained from a large group of patients mostly in aid of diagnosis of pregnancy. Patients with a variety of pathologic conditions also supplied specimens. There were a total of 1021 assays on 691 patients. It was possible to follow only 492 patients for 588 assays. There were 10 false positive and 2 false negative results for an overall accuracy of 98.0%. The mean level of HCG in normal pregnancies peaked at about 70,000 IU in the first trimester then fell to a constant level of 20,000 IU during the 2nd half of the pregnancy. The 95% confidence limits of the levels in normal pregnancy were from 10,000 to 350,000 IUD in the latter part of the first trimester and 2500-150,000 in the remainder. The levels of HCG in patients with clinical evidence of threatened abortion were determined. There were 86 such pregnancies, 47 of which had spontaneous abortion, while the remaining 39 went to term. The mean levels of the urinary HCG in the patients that aborted were consistently lower than those with normal pregnancies. Only during the period of 57-110 days after the last menstrual period were the values significant (P less than .001). 4 out of 6 patients with hydatidiform moles had titers of HCG greater than the normal range. HCG tests are also useful in following patients treated with chemotherapy for choriocarcinoma. The immunologic assay of HCG is a rapid, uncomplicated method of determining the level of HCG. It is of value in aiding the clinician in diagnosis, prognosis, and management of certain pathologic conditions of pregnancy.