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Afp4® Screening - Quadruple Marker Test (AFP, hCG, uE3, Inhibin A)


82105; 82677; 84702; 86336

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.

Test Details


Screening test for open neural tube defects (detects 80% open spina bifida, 90% anencephaly), Down syndrome (detects 75% to 80%), and trisomy 18 (detects 73%)


AFP Tetra; Alpha-Fetoprotein (AFP) Tetra Profile;

Test Includes

α-Fetoprotein, serum; dimeric inhibin A (DIA); human chorionic gonadotropin (hCG); unconjugated estriol (uE3)


Immunochemiluminometric assay (ICMA)

Pregnancy Week

14–21 Weeks

Discipline Code

BG (Biochemical Genetics)

Specimen Requirements


Whole blood; serum


Serum: 2-3 mL (unhemolyzed).
Whole Blood:  7 mL in SST or 10 ml in red-top tube; allow to clot; centrifuge (15 minutes at 1,000 g) to prevent hemolysis.


Serum:  AFP tube 
Whole Blood:  Serum separator tube (SST) or red-top tube.


Avoid hemolysis. Send complete specimen in the original tube. Do not pour off.

Special Instructions

Please Note: Ultrasound BPD (biparietal diameter) dating of pregnancy is preferred for optimal accuracy of risk calculations.

Causes for Rejection

Gross hemolysis; gross lipemia; quantity not sufficient for analysis

Storage Instructions

Maintain at room temperature

Additional Information




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