Cholinesteraza

Cholinesterase is an enzyme produced in the liver. It catalyses the hydrolysis of choline esters to choline and a fatty acid. It is a marker of the liver’s efficiency in the production of proteins. One of the indications for its determination is cirrhosis or liver cancer. The test involves taking blood from a vein in the arm once.

What is Cholinesterase?

Cholinesterase is secreted into the blood and causes it inactivation acetylocholiny – transmitter of the nervous system. This enzyme is also produced in the liver and pancreas. It is a marker of the liver’s efficiency in the production of proteins. Cholinesterase is also present in the intestinal mucosa, spleen, and nervous system. Testing of this enzyme is used primarily in the diagnosis of pesticide poisoning and liver diseases. Another indication is to check the susceptibility to succinylcholine before taking it. Cholinesterase deficiency can cause liver diseases (inflammation, cirrhosis), while its excess: hyperthyroidism. The reduction of cholinesterase is influenced, among others, by the use of hormonal contraception and chronic heart failure. Minimal lowering of cholinesterase concentration is also observed in pregnant women.

When do we perform a cholinesterase test?

The cholinesterase test allows you to assess the activity of: acetylcholinesterase (breaks down acetycholine into choline and acetic acid) and pseudocholinesterase (found in liver cells). These two enzymes are essential for the proper conduction of nerve impulses. We test the level of cholinesterase in the following situations:

1. Damage to hepatocytes (hepatitis, ischemia, cirrhosis, liver tumor). Considering that cholinesterase is produced in the liver, its test is a very good indicator of its efficiency.
2. Suspicion of poisoning with plant protection products – organophosphorus compounds. Poisoning with these substances may be evidenced by visual disturbances, constriction of the pupils, nausea, vomiting and headaches. When severe poisoning occurs, consciousness disorders, convulsions, decreased heart rate and even shock may occur. Poisoning usually occurs in people who have had contact with pesticides, which inhibit acetylcholinesterase and cause acetylcholine to accumulate in the body. Its excess has a negative effect on the human body.
3. Before surgery. Thanks to the examination, it is possible to assess the patient’s sensitivity to the drug used in anaesthesiology: succinylcholine. This preparation is broken down in the body by cholinesterase, hence it is very important to measure its activity. Succinylcholine is administered to the patient in order to relax the striated muscles, thus enabling the patient’s intubation. The lack of an adequate amount of cholinesterase and the patient’s strong hypersensitivity to succinylcholine may prolong the duration of the neuromuscular block and, consequently, lead to prolonged apnea after surgery.
4. In patients genetically at risk of developing apnea during surgery.

Cholinesterase – a study

1. Material for cholinesterase testing: serum. The taken blood sample is sent for analysis. The determination is performed by spectrophotometric methods, using the catalytic activity of the enzyme. The measurement is made using a biochemical analyzer.
2. Preparation for the test: on an empty stomach (at least 8 hours).
3. The course of cholinesterase testing: single blood sampling from a vein in the arm.
4. Time of waiting for the result: 1 day.
5. Norma: 5-12 U/ml
6. Comments: Plant protection products are chemically cholinesterase inhibitors. Poisoning with them causes excessive action of the mediator (transmitter) – acetylcholine, in post-ganglion fibers and in the neuromuscular plate. The clinical picture then shows reddening of the skin, a significant increase in bronchial secretion, constriction of the pupils, slower heart rate, and diarrhea.

There are no contraindications to the examination. There were also no complications.

Cholinesterase standards

The norm of cholinesterase is 5–12 U / ml. The result may vary depending on the laboratory in which we are doing the test. Note the standards listed next to your cholinesterase result.

How to Interpret Cholinesterase Results

The result below 5 U / ml, i.e. a reduced cholinesterase result, may be caused by:

1. pregnancy,
2. damage to liver cells due to inflammation or cirrhosis of the liver,
3. taken medications that inhibit the activity or synthesis of cholinesterase, e.g. cytostatics, contraceptives, organophosphorus compounds,
4. genetic disorders of cholinesterase synthesis,
5. malnutrition,
6. acute infection,
7. jaundice,
8. heart attack
9. tumor metastases.

Result above 12 U / ml, i.e. high cholinesterase level, may be caused by:

1. psoriasis,
2. secretory enteropathy,
3. an overactive thyroid gland,
4. nephrotic syndrome.