Normal cholinesterase level in the blood

Each laboratory must establish its own normal ranges for cholinesterase in the blood. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal levels, according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.

Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.

The normal ranges of cholinesterase in the blood may be very different from lab to lab depending of the type of cholinesterase measured (acetylcholinesterase, pseudocholinesterase or the sum of both), the sample (blood, plasma, serum, RBC), the technique or the substrate used to measure it. For that reason, it is very important to check the normal range that appears in your report.

Cholinesterase normal range in women is a bit lower than in men (10% or 15%). In newborns, normal ranges are usually half of the adult ones. The normal range of kids gradually increases to reach adult levels at 6 years old approximately.

In pregnancy, cholinesterase values are reduced a 20 or 30% in the first trimester, remaining decreased throughout the pregnancy and returning to normal range a few weeks after childbirth.

Cholinesterase is a family of enzymes made in the liver with an important role in the nervous system.

There are two types of cholinesterase:

• Acetylcholinesterase (also called erythrocyte cholinesterase or AChE): It is anchored to the external surface of RBC (Red Blood Cells) but it also present in tissues such as the lungs, the spleen, nerve endings and the gray matter of the brain.
• Pseudocholinesterase (also known as plasma cholinesterase, butyrylcholinesterase, or BuChE): It is primarily produced in the liver, but it is also found in the pancreas, the heart, the serum and in the white matter of the brain.

Acetylicholinesterase is responsible for the prompt hydrolysis of acetylcholine released at the nerve endings to mediate transmission of the neural impulse across the synapse. The biological role of pseudocholinesterase is still unknown.

A cholinesterase blood test has three main purposes:

• As a test of liver function: In the absence of genetic causes a decrease in cholinesterase activity reflects a liver disorder such as cirrhosis or hepatitis. It is also appropriate for monitoring liver function after liver transplantation.
• Perioperative management prior to anesthesia: Succinylcholine (suxamethonium) and mivacurium are drugs used in surgery as muscle relaxants. In patients with an uncommon genetic cholinesterase-deficiency disorder, the destruction of the drug will not occur rapidly enough, and the patient may suffer from paralysis of the respiratory muscles (apnea).
• As an indicator of possible insecticide poisoning: The inhalation, ingestion, or eye or skin contact with carbamate and organophosphorus pesticides (parathion, sarin, tetraethyl pyrophosphate, etc.) used in agriculture and in organic chemical industries may inhibit the cholinesterase activity. The degree of cholinesterase inhibition is proportional to the amount of exposure.

A high level of cholinesterase in the blood may be related to multiple diseases such as diabetes, hyperlipidemia, a high cholesterol level, hypertension, etc. If values are very high, it may be a sign of nephrotic syndrome.

The following values are considered to be normal values:

IMPORTANT: These levels are expressed in U/ml. They are an example of a healthy man of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.