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24892 Pseudocholinesterase, Total (PCHE1)

Pseudocholinesterase, Total (PCHE1)
Test Code: PCHOTSO
Synonyms/Keywords
Cholinesterase (Pseudo), Total,  Serum Cholinesterase (Pseudochol), Butyrylcholinesterase
Useful For
Monitoring exposure to organophosphorus insecticides
 
Monitoring patients with liver disease, particularly those undergoing liver transplantation
 
Identifying patients who are homozygous or heterozygous for an atypical gene and have low levels of pseudocholinesterase

​This tests is not useful for the differential diagnosis of jaundice.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Serum Separator Tube (SST) ​Red Top Tube (RTT) ​1 mL ​0.25 mL
Collection Processing Instructions
1. Patient's age and sex are required.
2. For cases of prolonged apnea following surgery, wait 24 hours before obtaining specimen.
3. Serum gel tubes should be centrifuged within 2 hours of collection.​
4. Red-top tubes should be centrifuged and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​ ​Refrigerated (preferred) ​14 days
​Frozen ​365 days
​Ambient​24 hours
Rejection Criteria
Hemolysis​Gross
LipemiaGross
Interference

There are some homozygous and heterozygous individuals who are sensitive to succinylcholine although their total pseudocholinesterase (PCHE) values are normal. A dibucaine inhibition test is necessary to confirm the presence of the abnormal allele in these individuals.

Certain drugs and anesthetic agents may produce in-vitro inhibition of the PCHE activity. Therefore, it is recommended that blood specimens be drawn 24 to 48 hours post-operatively on those patients who have experienced prolonged apnea after surgery.

Chemotherapy may interfere with test results, depending on the impact it has on the liver. PCHE levels may be lower due to this and if so, testing should be repeated at a later date.

Method Change: Pseudocholinesterase values measured after 1-28-2020 are approximately 80% increased compared to historical values and should be interpreted in the context of the current reference interval.

Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday; Continuously​ ​1 day
Colorimetric Assay​
Reference Lab
Test Information

​Serum cholinesterase, often called pseudocholinesterase (PCHE), is distinguished from acetylcholinesterase or "true cholinesterase," by both location and substrate.

Acetylcholinesterase is found in erythrocytes, in the lungs and spleen, in nerve endings, and in the gray matter of the brain. It is responsible for the hydrolysis of acetylcholine released at the nerve endings to mediate transmission of the neural impulse across the synapse.

PCHE, the serum enzyme, is also found in liver, pancreas, heart, and white matter. Its biological role is unknown.

The organophosphorus-containing insecticides are potent inhibitors of the true cholinesterase and also cause depression of PCHE. Low values of PCHE are also found in patients with liver disease. In general, patients with advanced cirrhosis and carcinoma with metastases will show a 50% to 70% decrease. Essentially normal values are seen in chronic hepatitis, mild cirrhosis, and obstructive jaundice.

PCHE metabolizes the muscle relaxants succinylcholine and mivacurium, and therefore, alterations in PCHE will influence the physiologic effect of these drugs.

In normal individuals (approximately 94% of the population) certain drugs and other agents, such as dibucaine and fluoride, will almost completely inhibit the PCHE activity.

A small number of individuals (<1% of the population) have been shown to have genetic variants of the enzyme, and cannot metabolize the muscle relaxants succinylcholine and mivacurium and experience prolonged apnea. These individuals generally have low levels of PCHE, which is not inhibited by dibucaine or fluoride. These individuals are either homozygotes or compound heterozygotes for an atypical gene controlling PCHE.

Simple heterozygotes have also been identified who show intermediate enzyme values and inhibition.

Reference Range Information
Performing Location Reference Range
​Mayo Clinic Laboratories Males:
5320-12,920 U/L
Females:
0-15 years: 5320-12,920 U/L
16-39 years: 4260-11,250 U/L
40-41 years: 5320-12,920 U/L
> or =42 years: 5320-12,920 U/L

Note: Females age 18-41 years who are pregnant or taking hormonal contraceptives, the reference interval is 3650-9120 U/L.

 

Interpretation
Patients with normal pseudocholinesterase (PCHE) activity show 70% to 90% inhibition by dibucaine, while patients homozygous for the abnormal allele show little or no inhibition (0%-20%) and usually low levels of enzyme.
 
Heterozygous patients have intermediate PCHE levels and response to inhibitors.
 
The atypical gene is inherited in an autosomal recessive pattern. In a positive patient, family members should be tested.
 
Decreasing or low levels may indicate exposure to organophosphorus insecticides, as long as liver disease and an abnormal allele have been ruled out.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82480
Synonyms/Keywords
Cholinesterase (Pseudo), Total,  Serum Cholinesterase (Pseudochol), Butyrylcholinesterase
Ordering Applications
Ordering Application Description
​Centricity ​None
​Cerner ​Pseudocholinesterase (8518)
​COM​Pseudocholinesterase (PCHE1)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Serum​ ​Serum Separator Tube (SST) ​Red Top Tube (RTT) ​1 mL ​0.25 mL
Collection Processing
1. Patient's age and sex are required.
2. For cases of prolonged apnea following surgery, wait 24 hours before obtaining specimen.
3. Serum gel tubes should be centrifuged within 2 hours of collection.​
4. Red-top tubes should be centrifuged and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​ ​Refrigerated (preferred) ​14 days
​Frozen ​365 days
​Ambient​24 hours
Rejection Criteria
Hemolysis​Gross
LipemiaGross
Interference

There are some homozygous and heterozygous individuals who are sensitive to succinylcholine although their total pseudocholinesterase (PCHE) values are normal. A dibucaine inhibition test is necessary to confirm the presence of the abnormal allele in these individuals.

Certain drugs and anesthetic agents may produce in-vitro inhibition of the PCHE activity. Therefore, it is recommended that blood specimens be drawn 24 to 48 hours post-operatively on those patients who have experienced prolonged apnea after surgery.

Chemotherapy may interfere with test results, depending on the impact it has on the liver. PCHE levels may be lower due to this and if so, testing should be repeated at a later date.

Method Change: Pseudocholinesterase values measured after 1-28-2020 are approximately 80% increased compared to historical values and should be interpreted in the context of the current reference interval.

Useful For
Monitoring exposure to organophosphorus insecticides
 
Monitoring patients with liver disease, particularly those undergoing liver transplantation
 
Identifying patients who are homozygous or heterozygous for an atypical gene and have low levels of pseudocholinesterase

​This tests is not useful for the differential diagnosis of jaundice.
Reference Range Information
Performing Location Reference Range
​Mayo Clinic Laboratories Males:
5320-12,920 U/L
Females:
0-15 years: 5320-12,920 U/L
16-39 years: 4260-11,250 U/L
40-41 years: 5320-12,920 U/L
> or =42 years: 5320-12,920 U/L

Note: Females age 18-41 years who are pregnant or taking hormonal contraceptives, the reference interval is 3650-9120 U/L.

 

Interpretation
Patients with normal pseudocholinesterase (PCHE) activity show 70% to 90% inhibition by dibucaine, while patients homozygous for the abnormal allele show little or no inhibition (0%-20%) and usually low levels of enzyme.
 
Heterozygous patients have intermediate PCHE levels and response to inhibitors.
 
The atypical gene is inherited in an autosomal recessive pattern. In a positive patient, family members should be tested.
 
Decreasing or low levels may indicate exposure to organophosphorus insecticides, as long as liver disease and an abnormal allele have been ruled out.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday; Continuously​ ​1 day
Colorimetric Assay​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​82480
For most current information refer to the Marshfield Laboratory online reference manual.