Test ID: ACHS
Acetylcholinesterase, Erythrocytes
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Detecting effects of remote (months) past exposure to cholinesterase inhibitors (organophosphate insecticide poisoning)
Method Name A short description of the method used to perform the test
Spectrophotometric-Thiocholine Production
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Cholinesterase
Insecticide Poisoning
Organo-Phosphate Poisoning
Paroxysmal Nocturnal Hemoglobinuria (PNH)
RBC Acetyl Cholinesterase
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen must arrive within 72 hours of draw.
Container/Tube: Lavender top (EDTA)
Specimen Volume: 4 mL
Additional Information: Date of draw is required.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild reject; Gross reject |
| Lipemia | Mild OK; Gross OK |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood EDTA | Refrigerated | |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Acetylcholinesterase (AChE) is anchored to the external surface of the RBC. Its appearance in a lysate of red cells is diminished in paroxysmal nocturnal hemoglobinuria (PNH). The use of red cell AChE for PNH has not gained widespread acceptance, and flow cytometry testing is most often used for PNH (see #81156 "PI-Linked Antigen, Blood").
Red cell AChE is most often used to detect past exposure to organophosphate insecticides with resultant inhibition of the enzyme. Both the pseudocholinesterase activity in serum and red cell AChE are inhibited by these insecticides, but they are dramatically different vis-a-vis the temporal aspect of the exposure. The half-life of the pseudo-enzyme in serum is about 8 days, and the "true" cholinesterase (AChE) of red cells is over 3 months (determined by erythropoietic activity). Recent exposure up to several weeks is determined by assay of the pseudo-enzyme and months after exposure by measurement of the red cell enzyme. The effect of the specific insecticides may be important to know prior to testing.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
31.2-61.3 U/g of hemoglobin
Interpretation Provides information to assist in interpretation of the test results
Activities less than normal are suspect for exposure to certain insecticides.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Make sure the potential offending agent is, indeed, an acetylcholinesterase inhibitor.
Pseudocholinesterase acitivity in serum is the appropriate test for succinylcholine sensitivity to anesthesia.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Robinson DG, Trites DG, Banister EW: Physiological effects of work stress and pesticide exposure in tree planting by British Columbia silviculture workers. Ergonomics 1993;36:951-961
2. Fuortes LJ, Ayebo AD, Kross BC: Cholinesterase-inhibiting insecticide toxicity. Am Fam Phys 1993;47:1613-1620
Method Description Describes how the test is performed and provides a method-specific reference
The substrate acetylthiocholine is split by acetylcholinesterase into thiocholine and acetate. The thiocholine then reacts with dithiobisnitro benzoic acid (Ellmans Reagent) to form the colored product thionitrobenzoic acid which is measured at 405 nm. (Ellman GL, Courtney KD, Andres V Jr, Featherstone RM: A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem Pharmacol 1961;7:88-95)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Tuesday, Friday; 10 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
82482
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| ACHSR | Acetylcholinesterase, RBC | 49230-6 |
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