Maternal Serum Screening, Integrated, Specimen #2, Alpha Fetoprotein, hCG, Estriol, and Inhibin A

Casandra

Casandra Test Code MC85433Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID FMSS2CPT Code 81511

Maternal Serum Screening, Integrated, Specimen #2, Alpha Fetoprotein, hCG, Estriol, and Inhibin A

Clinical Use

Use

The Maternal Serum Screening Integrated Test provides risk assessments for open neural tube defects, Down syndrome (trisomy 21), and trisomy 18 by analyzing maternal serum markers. This screening involves the measurement of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), estriol, and inhibin A. The test is part of a two-step process, with the first specimen typically taken in the first trimester and this second specimen taken between 14 to 24 weeks of gestation. By integrating results from both specimens, it offers a comprehensive evaluation that can guide further diagnostic testing or intervention.

Special Instructions

This test requires a previously performed first trimester specimen, specifically the Maternal Serum Screening, Integrated, Specimen #1, PAPP-A, NT. Specimen collection for the second sample must occur between 14 weeks, 0 days and 24 weeks, 6 days of gestation, with the recommended timeframe being 16 to 18 weeks gestation. Acceptable dates for this second specimen are outlined in the Integrated-1 report.

Limitations

Despite comprehensive screening, a result indicating "normal" may miss 15% of Down syndrome cases, 20% of open neural tube defects, and 10% of trisomy 18 cases. Abnormal results necessitate follow-up procedures, including targeted ultrasound and potential fetal diagnostic testing. It is crucial that the second specimen for sequential screening is received, as failure to do so will render the results uninterpretable, preventing any assessment of maternal risk.

Test Details

New York Approved