AFP, Maternal Risk Interpretation
Maternal serum alpha-fetoprotein (MSAFP) is used for prenatal screening. Maternal serum Alpha-Fetoprotein (AFP) elevation is associated with open neural tube defects, multiple gestation, placental anomalies, ventral abdominal wall defects, congenital nephrosis, and oligohydramnios. Follow-up for abnormal AFP results include genetic counseling, level II or III ultrasound examination and consideration of amniocentesis for chromosome and AFP analysis. MSAFP is not to be used as a screening test for chromosomal abnormalities.
Limitations: MSAFP results consistent with increased risk of NTD may be followed-up with appropriate diagnostic testing as detailed in the report. MSAFP does not screen for chromosomal abnormalities.
Prenatal risk assessment for open neural tube defects (NTDs).
The MSAFP test in pregnant women should be performed between 15.0 and 22.9 weeks gestational age, although the optimal period is 15.0-16.9 weeks. This time frame allows sufficient opportunity for further diagnostic studies if the initial MSAFP results are abnormal. Specimens submitted before 15.0 weeks or after 22.9 weeks gestation cannot be properly evaluated. Because MSAFP test results are influenced by certain patient characteristics, the following data must be provided with the specimen in order to permit accurate interpretation of results: date of collection, patient's (maternal) date of birth, patient's estimated date of delivery (EDD), patient's weight (in lbs.), patient's race, patient diabetic status (is patient insulin-dependent prior to pregnancy), number of fetuses, and whether this is a repeat sample.
1.0 mL Serum in a SST Gold Top Tube
1.0 mL Serum in a Red Top Tube (no gel)
14 days Ambient (Transport)
14 days Refrigerated
45 days Frozen
Collect specimen between 14-22 weeks gestation
Split serum into two tubes
Alpha-Fetoprotein 2-part Request Form must accompany the specimen (See Addendum A - AFP Form Example)
| AFP MoM: | |
| NTD | <2.50 |
| IDD | <1.90 |
| TWINS | <4.00 |
| TWINS IDD | <3.50 |
| TRIPLETS | <4.50 |
Maternal serum alpha-fetoprotein (MSAFP) is used for prenatal screening. Maternal serum Alpha-Fetoprotein (AFP) elevation is associated with open neural tube defects, multiple gestation, placental anomalies, ventral abdominal wall defects, congenital nephrosis, and oligohydramnios. Follow-up for abnormal AFP results include genetic counseling, level II or III ultrasound examination and consideration of amniocentesis for chromosome and AFP analysis. MSAFP is not to be used as a screening test for chromosomal abnormalities.
Limitations: MSAFP results consistent with increased risk of NTD may be followed-up with appropriate diagnostic testing as detailed in the report. MSAFP does not screen for chromosomal abnormalities.
3 to 4 days
False
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