A simple method for the early detection of pregnancy: (A) Comparative study with radioimmunoassay of beta-HCG: and (B) Fallacies compared to other immunological pregnancy tests.

A simple, sensitive and reliable non-radioactive method for the detection of hCG in concentrated urine for the diagnosis of early pregnancy is reported. Twenty ml of urine were sampled, filtered and concentrated by ultrafiltration with ultra-microporous membrane under reduced pressure (Immersible Molecular Separator, Millipore Co) and the hCG in the concentrate was detected by the ordinary latex agglutination inhibition method using beta-hCG antiserum to avoid cross-reaction with high levels of hLH and hMG. Concentrated and unconcentrated urine samples taken at different periods of amenorrhoea (1, 2 and 3 weeks) were also tested by two-slide pregnancy tests and one-tube pregnancy test. Blood and urine samples taken at one and two weeks amenorrhea were assayed for beta-hCG by a specific RIA. Results were compared to the new method. Retention characteristics and concentration efficacy of the ultra-microporous membrane were checked by performing recovery experiments using commercial hCG and lyophilization procedure. The new test proved to be more sensitive, specific and reliable than other nonradioactive methods in detecting low levels of urinary hCG for diagnosing pregnancy as early as one week after missed period in regularly menstruating women. In addition, it is simpler and safer than the serum RIA presently used to detect low levels of hCG.