Free Beta HCG in Dehradun

What is a Free Beta HCG?

Human chorionic gonadotropin is the pregnancy hormone, made by the placenta, and it is built from two subunits. The free beta subunit, circulating unattached, is measured separately because its level in the first trimester carries information that total hCG does not. It is one of two blood markers in the combined first-trimester screen, the other being PAPP-A, and these are interpreted together with the nuchal translucency measured on ultrasound and with maternal age to generate a numerical risk estimate for Down syndrome and certain other chromosomal conditions. In affected pregnancies free beta hCG tends to run higher than expected while PAPP-A runs lower, and the combination discriminates considerably better than either alone. Two things about this test are essential to understand. It is a screening test, producing a probability rather than an answer, and a high-risk result is not a diagnosis: the great majority of women who screen high-risk go on to have entirely healthy babies. And it depends completely on accurate dating, because levels change rapidly week by week, so a pregnancy dated wrongly produces a risk figure that is simply invalid.

Why take this test?

Free beta hCG is measured as part of the combined first-trimester screen, offered between about 11 and 13 weeks of pregnancy alongside the nuchal translucency scan. It is not ordered in isolation; the blood sample and the ultrasound are interpreted together, and a result reported without the scan cannot generate a meaningful risk. Its purpose is to identify pregnancies where the risk of a chromosomal condition is high enough to warrant offering a diagnostic test, such as chorionic villus sampling or amniocentesis, or the non-invasive prenatal test which analyses fetal DNA in the mother's blood. Screening is a choice rather than an obligation, and it is worth discussing with your obstetrician beforehand what you would do with a high-risk result, since that conversation is more useful before the test than after. Whatever the number, take it to your obstetrician rather than interpreting it yourself.

• Part of the combined first-trimester screen at 11 to 13 weeks
• Always interpreted with PAPP-A, nuchal translucency and maternal age
• Identifying pregnancies to offer diagnostic testing
• Where accurate pregnancy dating has been established by scan
• Screening by informed choice, discussed with your obstetrician
• Not meaningful as a standalone blood test

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