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Test Code Billings Clinic: 9116 Integrated Genetics: 325 AFP4® Maternal, Serum, Integrated Genetics

Performing Laboratory

Integrated Genetics

Useful For

Afp4 screens for fetal Down syndrome, trisomy 18 and open neural tube defects between 15 weeks / 0 days and 21 weeks / 6 days (15.0-21.9 weeks). Optimal time is between 16 and 18 weeks. Four biochemical markers, alphafetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3) and dimeric Inhibin-A are analyzed in a maternal serum sample to provide risk assessments for Down syndrome, trisomy 18 and open neural tube defects in the second trimester.for fetal Down syndrome, trisomy 18 and open neural tube defects between 15 weeks / 0 days and 21 weeks / 6 days (15.0-21.9 weeks). Optimal time is between 16 and 18 weeks. Four biochemical markers, alphafetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3) and dimeric Inhibin-A are analyzed in a maternal serum sample to provide risk assessments for Down syndrome, trisomy 18 and open neural tube defects in the second trimester.

Methodology

Immunochemiluminometric assay (ICMA)

Specimen Requirements

Contact Billings Clinic Laboratory at 866-232-2522 prior to specimen draw for specific instructions.

  • Draw blood in a serum gel tube(s).
  • Spin down and send 3 mL of maternal serum refrigerated.
  • If there is a delay in transport of ≥7 days, send specimen frozen in plastic vial.

Note: The following information is required for processing:


1. Maternal date of birth (not age), weight, and race

2. Number of fetuses in this pregnancy
3. Is patient an insulin-dependent diabetic?
4. Family history of neural tube defect (NTD)?
5. Previous Down syndrome pregnancy?
6. Gestational age calculation (provide at least 1 of the following):


A. Gestation by ultrasound on the date ultrasound was performed
Note: Do not extrapolate to draw date.
B. First day of last menstrual period
C. Gestation by physical exam
D. Expected date of delivery (EDD)

Reject Due To

  • Gross hemolysis
  • Gross lipemia
  • Quantity not sufficient for analysis

Reference Values

Reference values are included with patient’s report.

Day(s) Test Set Up

Monday through Saturday

Test Classification and CPT Coding

82105 - AFP

82677 - uE3

84702 - hCG, total

86336 - inhibin-A