Cholinesterase

Pseudocholinesterase

10 days

Spectrophotometry (Ellman) − kinetic

Causes for Rejection
Whole blood specimen (a 20% to 25% increase can occur over a 24-hour period if serum is left on the clot); hemolysis

Accredited Laboratory Partner

Contact Technical Support

This test is used to evaluate preoperative patients for succinylcholine (suxamethonium) anesthetic sensitivity, genetic or secondary to insecticide exposure, in appropriate circumstances, and to prevent or evaluate prolonged anesthetic effect, prolonged apnea, after surgery. Very small amounts (0.04−0.06 mg/kg) of succinylcholine are needed to obtain 90% of neuromuscular blockade in patients with low levels of plasma cholinesterase activity.1

Monitor organophosphorous or carbamate insecticide poisoning, in which level is decreased; establish patient's baseline value before exposure. Indications include such pesticide exposure, especially with miosis, blurred vision, muscle weakness, twitching, and fasciculation, bradycardia, nausea, diarrhea, vomiting, salivation, sweating, pulmonary edema, arrhythmias, and convulsions. The value of assessing risk status in persons exposed to organophosphate insecticides on the basis of plasma or serum cholinesterase levels alone has been called into question.2 Are normal levels indicative of no exposure or of a genetic variant with or without exposure? There are interpretive problems with low or high values.2

Family studies may be done when an individual with a genetically abnormal type is documented by serum pseudocholinesterase deficiency and, ideally, confirmed by phenotyping.

Serum

0.5 mL

Red-top tube or gel-barrier tube

No special preparation is required for this test. You may eat, drink, and take your medications as normal, unless instructed otherwise by your healthcare provider.

Separate serum from cells immediately after clotting (30 minutes) and place in transport tube. Mark transport tube “serum”.