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HelpTest Code ACHE_ Acetylcholinesterase, Amniotic Fluid
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
1. Gestational age at amniocentesis is required.
2. If not ordering electronically, provide gestational age on Second Trimester Maternal Screening Alpha-Fetoprotein / Quad Screen Patient Information (T595) and send with specimen.
Specimen Required
Container/Tube: Amniotic fluid container
Specimen Volume: 1 mL
Collection Instructions: Specimen must be collected between 14 to 21 weeks gestation; 14 to 18 weeks is preferred.
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 |
Useful For
Diagnosing open neural tube defects and, to a lesser degree, ventral wall defects
Reject Due To
| Gross hemolysis | OK |
| Gross icterus | OK |
Day(s) Performed
Tuesday, Thursday
Report Available
3 to 7 daysReporting Name
Acetylcholinesterase, AFReference 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.
Method Name
Polyacrylamide Electrophoresis
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82013