A critical study of immunological methods for pregnancy diagnosis

Abstract

sYNopsIs Immunological methods of pregnancy diagnosis using both tanned red cell and latex particles are compared in a series of women (up to the fourteenth week of gestation) and also in negative controls. The tanned red cell test showed slightly more accurate and sensitive results throughout the trial. In 31 samples also submitted for the Hogben test the immunological test showed marginal superiority. It is concluded that immunological methods are reliable for the diagnosis of pregnancy at least between the fifth and the fourteenth weeks of gestation.When Brody and Carlstrom (1960) reported the production of antibodies to human chorionic gonadotrophin they created the possibility of a simple test for pregnancy based on immunological methods. Two such tests, one dependent upon the use of tanned red cells (Fulthorpe, Parke, Tovey, and Monckton, 1963) and the second using coated latex particles (Henry and Little, 1962), are now available. This paper is concerned with a controlled trial of two of these materials. MATERIALS AND METHODSSamples of urine were obtained from new patients attending the antenatal clinic and submitted directly to the laboratory. Patients were then asked to send by post the early morning specimen obtained next day and thereafter to submit further specimens weekly until the fourteenth week of gestation. Negative controls were introduced into this series by the clinician in charge of the antenatal clinic who obtained specimens from patients who were known to be not pregnant at the time and submitted them to the laboratory in such a way that they were indistinguishable from specimens obtained from the clinic. In this part of the series 107 patients (including negative controls) provided 554 specimens.In order to study the results obtained in very early pregnancy members of the hospital staff and a number of local general practitioners were invited to submit specimens obtained from patients whom they thought were in very early pregnancy. A total of 255 additional specimens obtained from 131 patients was added to the series in this group.The influence of menopausal gonadotrophin was studied by testing urines from 25 post-menopausal women in general medical wards.