Alpha‑Fetoprotein and Acetylcholinesterase, Amniotic Fluid with Reflex to HbF
Use
Measurement of alpha‑fetoprotein (AFP) in amniotic fluid is used to evaluate for open neural tube defects (ONTDs), ventral wall defects, and other fetal abnormalities. Reflex testing for acetylcholinesterase (AChE) and fetal hemoglobin (HbF) is performed when AFP multiple of median (MoM) is ≥2.0 to distinguish true fetal neural tube defects from spurious elevation due to fetal blood contamination, with the presence of AChE supportive of open neural tube or abdominal wall defects.
Special Instructions
Specimen requirement: 2.4 mL (1.2 mL minimum) amniotic fluid collected in a sterile, leak‑proof container. Reflex testing for AChE and HbF occurs automatically when AFP MoM ≥ 2.0, at an additional charge. Performing site is Quest Diagnostics Nichols Institute, San Juan Capistrano; test not available for New York patient testing (use code 91399 instead).
Limitations
This assay cannot detect subtle chromosomal rearrangements, microdeletion syndromes, or single‑gene disorders. Mosaicism below ~14% may not be detected. Substantial fetal hemorrhage into the fluid may elevate both AFP and AChE, potentially confounding interpretation.
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Amniotic Fluid
Volume
2.4 mL
Minimum Volume
1.2 mL
Container
sterile, leak‑proof container
Other tests from different labs that may be relevant