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HelpTest Code AFP-1 Maternal Serum Screen Single Test Panel AFP (MSAFP)
Useful For
Useful for prenatal screening of open neural tube defects only (ONTD). The screen is performed by measuring AFP in maternal serum. This test does not reliably detect closed, or very small neural tube defects.
Synonyms/Keywords
AFP (maternal), MSAFP, ALPHA FETOPROTEIN-1, AFP-1, AFP-1 (Single Marker MSS)
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Serum | Serum Separator Tube (SST) | Red Top Tube (RTT) | 2.0 mL | 0.3 mL | 0.25 mL |
Collection/Processing Instructions
Sample must be drawn between 15 weeks/0 day and 21 weeks/6 days gestation.
Samples collected in gel barrier tubes must be removed from the primary tube prior to transporting to Marshfield.
Do not send the primary collection tube.
Samples collected in a RTT must be removed from the cells within one hour for storage or transport.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Ambient | 8 hours |
| Refrigerated | 7 days | |
| Frozen | >7 days |
Rejection Criteria
Grossly hemolyzed
Test Information
A completed Marshfield Labs Maternal Serum Request Requisition Form must accompany the specimen or the information must be entered during order entry in Clinical Order Manager. These forms can be obtained calling 800-222-5835. The abnormal reports are faxed to the Provider by Marshfield Clinic Medical Genetics staff. Maternal Serum Screen Request (AFP Form)
It is recommended that women who have the first trimester screening for aneuploidy should not undergo second trimester quadruple screening. If first and second trimester screens are performed for the same disorder, the false positive rates are additive and therefore, can lead to unnecessary invasive procedures. However, if women who have first trimester screening performed for aneuploidy and wish to assess their risk for an open neural tube defect, the AFP-1 test should be ordered.
Interpretations
An AFP MoM < 2.5 is reported as Screen-negative.
A Screen-negative result indicates that the calculated alpha-fetoprotein (AFP) multiple of the median (MoM) falls below the established cut-off of 2.50 MoM. A negative screen does not guarantee the absence of NTDs.
AFP MoM of 2.5 (singleton pregnancy) is reported as Screen-positive.
A Screen-positive result indicates an increased risk for open NTDs. It does not infer a definitive diagnosis of a NTD, but indicates that further evaluation should be considered.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield | See interpretative report |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Friday | 1 day | Two-site Immunoenzymatic Assay/Beckman Coulter DXI |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82105 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82105 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | AFP (Maternal Serum) (AFP-1) |