Alpha-Fetoprotein (AFP) Tetra Profile

Additional Information:

UFHPL Epic order code: LAB4509


  • 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

CPT Code(s):

82105, 82677, 84702, 86336

Collection Procedure:

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

Specimen Requirements:

Type: Serum
Container/Tube: Gel-barrier tube (no thrombin additive)

Sample Volume: 5 mL

Minimum Volume: 3 mL

Storage: Store specimens at room temperature after collection.

Stability (collection to time of analysis/testing):

  • Ambient: 7 days
  • Refrigerated: 14 days
  • Frozen: 14 days
  • Freeze/Thaw cycles: Stable (x3)
Rejection Criteria:

  • Gross hemolysis
  • Gross lipemia
  • Quantity not sufficient for analysis (QNS samples)


This is a screening test for:

  • Open neural tube defects (detects 80 percent of open spina bifida and 90 percent of anencephaly)
  • Down syndrome (detects 75 to 80 percent)
  • Trisomy 18 (detects 73 percent)


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


Immunochemiluminometric assay (ICMA)