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A comparison of total and free β‐HCG assays in Down syndrome screening
Author(s) -
Stone S.,
Henley R.,
Reynolds T.,
John R.
Publication year - 1993
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.1970130617
Subject(s) - medicine , down syndrome , pregnancy , gynecology , alpha fetoprotein , prenatal screening , obstetrics , prenatal diagnosis , fetus , biology , genetics , psychiatry , hepatocellular carcinoma
Free β‐HCG is a new analyte that has been suggested to be superior to total HCG when used in combination with alpha‐fetoprotein (AFP) for Down syndrome risk screening in early pregnancy. We have evaluated this claim on 21 samples collected from Down syndrome pregnancies and 180 samples from unaffected pregnancies. The detection rates for the combination of AFP with free β‐HCG or the combination of AFP with total HCG were identical (71 per cent) but the initial screen positive rate (equivalent to the false‐positive rate) was 7·5 per cent for AFP+free β‐HCG screening compared with 3·5 per cent for AFP+ total HCG screening. We conclude that the case for free β‐HCG is unproven and suggest that further data be collected before free β‐HCG becomes acceptable.