What is cholinesterase?
Cholinesterase (ChE) is an enzyme that cleaves various chemical compounds in the body, namely cholinesters. There are two subtypes of cholinesterase, ChE I and ChE II. However, only the latter, also called pseudocholinesterase, can be measured in the blood. It is produced in the liver. Therefore, it is also a good marker for the synthesis function and thus the functionality of the liver cells.
What is cholinesterase I?
When do you determine cholinesterase?
Since cholinesterase II is an indicator of liver synthesis capacity, the physician determines the blood value when liver damage is suspected. This results, for example, from classic symptoms of liver disease:
- yellowing of the skin or conjunctiva
- Thin, parchment-like skin (skin atrophy)
- neoplasms of superficial small arteries (spider naevi) or visible veins in the umbilical region (caput medusae)
- Itching
- palpable enlargement of the liver, increase in abdominal girth
- possible spleen enlargement
Nonspecific general complaints such as reduced performance, fatigue or abdominal pain may also be an indication of liver disease.
What ChE value is normal?
Since cholinesterase I is not present in the blood, the blood ChE value refers only to cholinesterase II.
For the female gender, the following normal values apply (U/l = enzyme units per liter):
|
Normal range (U/l) |
|
|
up to 15 years |
|
|
16 to 17 years |
4.250 – 11.250 |
|
18 to 40 years |
4.260 – 11.250 |
|
over 40 years |
5.320 – 12.920 |
|
Pregnancy |
3.650 – 9.120 |
For the male gender, the following cholinesterase standard values apply:
|
Normal range (U/l) |
|
|
up to 15 years |
5.320 – 12.920 |
|
16 to 17 years |
4.260 – 11.250 |
|
from 18 years |
5.320 – 12.920 |
When is cholinesterase decreased?
Cholinesterase deficiency is found when liver function is impaired. This can have various causes:
- Liver cirrhosis
- hepatocellular carcinoma or liver metastases
- congested liver in right heart failure
- toxic liver damage, for example due to alcohol or fungal toxins
- poisoning with organophosphates (for example with the insecticide parathion)
- poor nutritional status
- extensive burns
- kidney failure with dialysis requirement
- hypothyroidism (underactive thyroid gland)
When is cholinesterase elevated?
A common cause of elevated levels is an increased concentration of dietary fats in the blood (hyperlipidemia). It occurs, for example, in obesity or diabetes mellitus. Other reasons for increased cholinesterase include:
- alcoholic fatty liver
- protein loss, for example due to nephrotic syndrome
- Coronary heart disease (CHD)
What to do if cholinesterase levels are altered?
If cholinesterase is altered, the doctor must determine the underlying cause. If he has not already done so, he will determine other liver values. In addition, he can assess liver size and structure with an ultrasound examination. If a genetic disorder of cholinesterase is suspected, the physician can also perform a genetic analysis using a blood sample.