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Title | Maternal Serum Alpha-Fetoprotein |
Specimen Requirement | <p>1-SST/1.0 mL serum. Spin, separate serum from cells within 2 hours of collection. <strong>Completed Prenatal Info sheet must accompany sample.</strong></p> |
Methodology | |
Stability | Refrigerated 48 hours; Frozen 14 days |
Reference Range | By report* |
Turnaround | 2-3 days |
Clinical Use | <p>The performance of this test varies with maternal age and other clinical parameters. Recent research suggests that second trimester maternal serum screening of alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin and inhibin A (the Quad Screen) has 81% sensitivity for Down syndrome detection and a false-positive rate of 7%. This use is considered to be investigational. Follow-up testing is recommended for patients when the calculated second trimester Down syndrome risk is greater than or equal to 1: 270. Normal serum AFP levels for neural tube defects (NTD) are less than 2.0 multiples of the median (MoM). Normal values exclude approximately 95% of cases of anencephaly, 80% of cases of spina bifida, and 85% of ventral wall defects. Closed dysraphic states and small defects generally constitute the group in which total exclusion is not possible.</p> |
Test Code | MSAFP |
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