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HelpOrder Code LABMAFP1 Alpha-Fetoprotein (AFP), Single Marker Screen, Maternal, Serum
Additional Codes
Mayo Test Code: MAFP1
Epic Test Code: LABMAFP1
Necessary Information
In order to provide the best results, either answer the order entry questions or provide the required information using the Second Trimester Maternal Screening Alpha-Fetoprotein / Quad Screen Patient Information (T595).
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Do not collect specimen after amniocentesis as this could affect results.
2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.
Additional Information:
1. Collect blood between 15 weeks, 0 days and 22 weeks, 6 days.
2. Initial or repeat testing is determined in the laboratory at the time of report and will be reported accordingly. To be considered a repeat test for the patient, the testing must be within the same pregnancy and trimester, with interpretable results for the same test, and both tests are performed at Mayo Clinic.
Forms
1. If not ordering electronically, Second Trimester Maternal Screening Alpha-Fetoprotein / Quad Screen Patient Information (T595) is required.
2. If not ordering electronically, complete, print, and send a General Request (T239).
Useful For
Prenatal screening for open neural tube defect
Special Instructions
Method Name
Two-Site Immunoenzymatic (Sandwich) Assay
Reporting Name
AFP Single Marker SCRN, Maternal, SSpecimen Type
SerumSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days |
| Frozen | 90 days | |
| Ambient | 7 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
An alpha-fetoprotein (AFP) multiple of the median (MoM) <2.5 is reported as screen negative.
AFP MoM ≥2.5 (singleton and twin pregnancies) are reported as screen positive.
An interpretive report will be provided.
Method Description
Alpha-fetoprotein (AFP) values are compared to the median value for the unaffected population at a given gestational age and the multiple of the median is obtained and classified as either screen-positive or screen-negative. The Access AFP assay is a 2-site immunoenzymatic sandwich assay. A sample is added to a reaction vessel with mouse monoclonal anti-AFP alkaline phosphatase conjugate and paramagnetic particles coated with a second mouse monoclonal anti-AFP antibody. The AFP in the sample binds to the immobilized monoclonal anti-AFP on the solid phase while, at the same time, the monoclonal anti-AFP-alkaline phosphatase conjugate reacts with different antigenic sites on the sample AFP. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then the chemiluminescent substrate Lumi-Phos*530 is added to the reaction vessel and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the amount of AFP in the sample. The amount of analyte in the sample is determined by means of a stored multipoint calibration curve.(Instruction manual: Access AFP. Beckman Coulter, Inc; 2024)
Day(s) Performed
Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82105