Sign in →

Test Code LAB3595 Acetylcholinesterase, Amniotic Fluid

Additional Codes

Mayo Test ID

Reporting Name

Acetylcholinesterase, AF

Useful For

Diagnosing open neural tube defects and, to a lesser degree, ventral wall defects

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Amniotic Fld

Additional Testing Requirements

If chromosome studies are also requested, see CHRAF / Chromosome Analysis, Amniotic Fluid for specimen requirements. When requested with chromosome analysis, the specimen cannot be frozen.

Necessary Information

Gestational age at amniocentesis is required.

Specimen Required

Container/Tube: Amniotic fluid container

Specimen Volume: 1 mL

Collection Instructions: A specimen from the 14 to 18 week gestational period of pregnancy is preferred. Amniotic fluid from the 14 to 21 week gestational period is acceptable.

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Amniotic Fld Refrigerated (preferred) 365 days
  Frozen  365 days
  Ambient  14 days

Reference Values

Negative (reported as negative [normal] or positive [abnormal] for inhibitable acetylcholinesterase)


Reference values were established in conjunction with alpha-fetoprotein testing and include only amniotic fluids from pregnancies between 14 and 21 weeks gestation.

Day(s) and Time(s) Performed

Thursday; 8 a.m. (not reported on Saturday and Sunday)

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
ACHE_ Acetylcholinesterase, AF 30106-9


Result ID Test Result Name Result LOINC Value
9287 Acetylcholinesterase, AF 30106-9
GACHE Gestational Age (ACHE) 18185-9

Method Name

Polyacrylamide Electrophoresis


1. Second Trimester Maternal Screening Alpha-Fetoprotein (AFP)/QUAD Screen Patient Information (T595) is required; see Special Instructions.

2. Biochemical Genetics Patient Information (T602) in Special Instructions.