Alpha-fetoprotein, Maternal Serum (MSAFP)

Prenatal Screening Laboratory

Immunoassay

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Specimen Required:

Serum: 2 mL

Room temperature or 4°C

15 - 25 weeks gestation

Days Test Set Up:

Monday - Friday

Analytic Time:

48 hours

Reference Values:

Reference ranges are dependent on demographic and clinical factors.

Screening cutoff is 2.0 MoM.

CPT Code(s):

82105

Relevance:

Elevated MSAFP levels are associated with open fetal defects such as spina bifida, anencephaly, gastroschisis, and omphalocele.

Notes:

Interpretation is highly dependent on gestational age, race, insulin dependent diabetes, maternal weight, and family history. Patient pamphlets titled Understanding Spina Bifida, Understanding Anencephaly and Understanding Ventral Wall Defects are available from the FBR. MSAFP as a single marker for Down syndrome screening has been superceded by and is included in multiple marker screening (see AFP Profile and AFP Profile Four). MSAFP is appropriate following first trimester Down syndrome screening or diagnosis.

Elevated results are telephoned to referring physician or laboratory.

Reference(s)

• Wald NJ, Cuckle HS: Maternal serum alpha-fetoprotein measurement in antenatal screening for anencephaly and spina bifida in early pregnancy. Report of the U.K. Collaborative Study on Alpha-fetoprotein in Relation to Neural Tube defects. Lancet, i:1323-1332, 1977.