Test Catalog

Test Id : ACHS

Acetylcholinesterase, Erythrocytes

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detecting effects of chronic or 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

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Acetylcholinesterase, RBC

Lists additional common names for a test, as an aid in searching



Insecticide Poisoning

Organo-Phosphate Poisoning

RBC Acetyl Cholinesterase

Specimen Type
Describes the specimen type validated for testing

Whole Blood EDTA

Ordering Guidance

For testing succinylcholine sensitivity to anesthesia, order PCHE1 / Pseudocholinesterase, Total, Serum.

Shipping Instructions

Specimen must arrive within 72 hours of collection.

Necessary Information

Date of collection is required.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Container/Tube: Lavender top (EDTA)

Specimen Volume: 4 mL

Collection Information: Send whole blood specimen in original tube. Do not aliquot.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

2.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Whole Blood EDTA Refrigerated 72 hours

Useful For
Suggests clinical disorders or settings where the test may be helpful

Detecting effects of chronic or remote (months) past exposure to cholinesterase inhibitors (organophosphate insecticide poisoning)

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Erythrocyte acetylcholinesterase (AChE) activity is measured to evaluate possible exposure to organophosphate insecticides. Organophosphates act by irreversible inhibition of AChE. Inhibition of AChE in humans causes a variety of acute symptoms including dizziness, nausea, difficulty breathing, and even death. The presence and severity of these symptoms depend, in part, on the degree of AChE depression.


Occupational pesticide handlers are at an elevated risk for exposure to these chemicals through skin contact, inhalation, or accidental ingestion. Organophosphate intoxication can be a result of one or more high exposure events or through chronic lower-level exposure.


Both serum and erythrocyte cholinesterase activity are inhibited by these insecticides, which are among the most commonly used pesticides in the United States. The half-life of serum cholinesterase (eg, pseudocholinesterase) is about 8 days, while the half-life of AChE in erythrocytes is between 2 and 3 months. Therefore, erythrocyte AChE is an indicator of chronic and temporally distant exposures to organophosphates.

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


Reference values have not been established for patients younger than 18 years of age.

Provides information to assist in interpretation of the test results

Activities less than normal are suspect for exposure to certain insecticides. For occupational high-risk individuals, a pre-exposure "baseline" is recommended.

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.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Brahmi N, Mokline A, Kouraichi N, et al: Prognostic value of human erythrocyte acetylcholinesterase in acute organophosphate poisoning. Am J Emerg Med. Nov 2006;24(7):822-827. doi: 10.1016/j.ajem.2006.05.009

2. Strelitz J, Engel LS, Keifer MC: Blood acetylcholinesterase and butyrylcholinesterase as biomarkers of cholinesterase depression among pesticide handlers. Occup Environ Med. 2014;71(12):842-847. doi: 10.1136/oemed-2014-102315

3. Mason HJ: The recovery of plasma cholinesterase and erythrocyte acetylcholinesterase activity in workers after over-exposure to dichlorvos. Occup Med (Lond). 2000;50(5):343-347. doi: 10.1093/occmed/50.5.343

4. Assis CR, Linhares AG, Cabrera MP, et al: Erythrocyte acetylcholinesterase as a biomarker of pesticide exposure: new and forgotten insights. Environ Sci Pollut Res. 2018;25:18364-18376. doi: 10.1007/s11356-018-2303-9

5. Robinson DG, Trites DG, Banister EW: Physiological effects of work stress and pesticide exposure in tree planting by British Columbia silviculture workers. Ergonomics. 1993 Aug;36:951-961. doi: 10.1080/00140139308967959

6. Fuortes LJ, Ayebo AD, Kross BC: Cholinesterase-inhibiting insecticide toxicity. Am Fam Phys. 1993 May;47:1613-1620

Method Description
Describes how the test is performed and provides a method-specific reference

Acetylcholinesterase activity is determined by automated photometric method and hemoglobin is measured by spectrophotometric analysis of lysates from washed packed erythrocytes.(Package insert: Cholinesterase, Roche Diagnostics; V10.0, 02/2017)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.


Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

4 to 8 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

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 instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

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 Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
ACHS Acetylcholinesterase, RBC 49230-6
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
ACHSR Acetylcholinesterase, RBC 49230-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports