Plasma Cholinesterase Activity (Pseudocholinesterase Activity)
This test measures the activity level of cholinesterase, an enzyme found in your blood that helps break down certain medications and chemicals.
["Cholinesterase helps your body process medications and toxins; low levels may indicate genetic variations or conditions affecting enzyme function."]
Key facts at a glance
- LOINC
- 2097-4
- Short code
- Cholinesterase Amn-cCnc
- Synonyms
- Cholinesterase Amn-cCnc
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you’re about to receive certain medications, such as anesthesia or some antibiotics, that rely on cholinesterase to be safely metabolized in your body. It’s also used to screen for rare genetic conditions that can affect enzyme levels, like congenital myasthenic syndromes or certain drug reactions.
What to Expect During the Test
A small blood sample is taken from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The sample is then sent to a lab for analysis.
What the Results Mean
Results are typically reported as an activity level (units per liter or milliliters per minute), which helps determine if your enzyme levels are within a normal range or if adjustments to medications are needed. Normal ranges can vary slightly by lab.
Possible Causes of Abnormal Results
Low cholinesterase activity may be due to genetic predisposition, liver disease, or certain medications. High levels are less common but could indicate liver dysfunction or other metabolic conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Plasma Cholinesterase
Frequently asked questions
Low cholinesterase activity can increase the risk of side effects from medications that rely on this enzyme, such as prolonged muscle weakness or nerve damage. This test helps prevent adverse reactions by ensuring safe dosing.
If you have a family history of rare enzyme disorders or are taking medications known to interact with cholinesterase, your provider may recommend this test before surgery or treatment.
What happens if my results are low? Will I need to change my medication?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy