Abderhalden's Biological Test of Pregnancy. 73 



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Abderhalden's biological test of pregnancy. 



By P. F. Williams and R. M. Pearce. 



[From the John Herr Musser Department of Research Medicine, 

 University of Pennsylvania, .] 



Summary. 



The use of Abderhalden's test for pregnancy, employing the 

 dialysis method and the ninhydrin color reaction has given 

 positive results with each of 28 sera from pregnant women and 

 with eight from women in the post-partum period, including one 

 abortion. The test has never been negative in a known preg- 

 nancy. On the other hand, the serum of pregnancy reacts with 

 tissues (kidney, heart, uterus) other than placenta. Also sera of 

 two cases of nephritis, one of tabes and one of infection (carbuncle), 

 and occasionally of some individuals in apparent perfect health 

 have given the reaction with placenta and other tissues. 



In the use of Abderhalden's dialysis method we have found 

 the ninhydrin reaction far superior to the biuret reaction. It is 

 also important that Schleicher and Schull's smaller dialysis sacks 

 should be used rather than the fish skin membranes originally 

 recommended. 



Results as satisfactory as those obtained by dialysis are ob- 

 tained by mixing tissue and serum in tubes and after incubating 

 for 24 hours testing the filtrate obtained on coagulation by heat 

 and acetic acid with ninhydrin. 



Inactivation of the serum causes a great diminution in the 

 degree of reaction, but does not cause it to disappear entirely. 

 At zero temperature no reaction occurs. The power of a serum 

 to cause the reaction persists when the serum is kept under proper 

 conditions of temperature for at least 7 days. 



As the result of our studies we feel that this test cannot be 

 accepted as an accurate clinical method until it has been more 

 thoroughly investigated and the possible sources of error corrected. 

 This conclusion however applies only to Abderhalden's dialysis 

 method and not to his optical method with which we have had 

 no experience. 



