Immuno-filtration. a new principle of analysis exemplified by the determination of HCG
Daae, L.N.; Daae, C.; Jerve, F.; Torjesen, P.; Arnesen, T.
Tidsskrift for den Norske Laegeforening Tidsskrift for Praktisk Medicin Ny Raekke 108(16): 1305-1308
1988
ISSN/ISBN: 0029-2001 PMID: 3291193 Document Number: 307654
A rapid quantitative test for human chorionic gonadotropin (HCG) is useful for diagnosis of extra-Uterine pregnancy. The development of monoclonal antibodies has made it possible to produce immuno-filters of very high specific sensitivity. The reported tests were performed on samples from 90 patients with varying diagnoses. The HCG levels determined in the tests were checked against radioimmunoassay tests standardized to World Health Organization 1st international standard. Urine has traditionally been the sample material for simple tests of HCG, but early tests were easily spoiled by any protein present in the urine, for example, from weak hematuria. The new immuno-filtration technique washes protein and other interfering materials away. The new technique is better suited for measuring HCG concentration in serum since the HCG concentration does not vary so much as it does in urine. The Tandem Icon HCG Hybritech test has been found to be nearly 100% specific and 100% sensitive. The extremely high sensitivity which will show a positive test many days before expected menstruation for normal pregnancy. There is a disadvantage in that perhaps 50% of all initial pregnancies are spontaneously aborted in the course of the 1st few weeks of pregnancy. False hopes can be aroused. By timing the development of the blue indicator spot with a stopwatch, changes in HCG concentration may be plotted over time for a patient for better control of the pregnancy diagnosis.