Alpha-Fetoprotein (AFP) Tetra Profile

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Turnaround Time: 2 -5 days
CPT Code:

[MAAA: 81511] or 82105; 82677; 84702; 86336

Test Type: 5 mL, Serum
Stability Time:



Room temperature

7 days


14 days


14 days

Freeze/thaw cycles

Stable x3


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 is a screening test. A positive AFP tetra result means that more diagnostic testing may be offered to the pregnant woman to determine if a neural tube defect or chromosome abnormality is present.

Haddow JE, Palomaki GE, Knight GJ, Foster DL, Neveux LM. Second trimester screening for Down's syndrome using maternal serum dimeric inhibin A. J Med Screen. 1998; 5(3):115-119. PubMed 9795869

Collection Details:

Collection Instructions:

The following information must be provided: gestational age, date on which the patient was the stated gestational age, how gestational age was determined (LMP, EDD, US), patient's weight, patient's date of birth, patient's race (white, black, other), and insulin-dependent diabetic status. Also indicate relevant patient history (eg, prior neural tube defects, Down syndrome, ultrasound anomalies, or previous maternal serum screening specimen during this pregnancy). Complete information is necessary to interpret the test. Patient information may be provided to the laboratory using The Maternal Prenatal Screening requisition form 0900. Specimens must be collected before amniocentesis.

Down syndrome screening is offered for gestational ages 15.0 to 21.9 weeks. Open spina bifida screening is offered for gestational ages 15.0 to 23.9 weeks. The optimal gestational age for open spina bifida screening is 16.0 to 18.9 weeks.

Gel-barrier tube.

Collect in serum separator tube with gel barrier. Allow blood to clot, avoiding hemolysis. Separate serum from cells by centrifugation. Transport spun tube to testing laboratory.

Pour-off is not advised. Maternal serum specimens must be drawn prior to amniocentesis to avoid contamination with fetal blood.