Transaminases (ASAT and ALAT) are enzymes present inside cells. They are good markers of heart and liver disease. When to worry? How to interpret the results of the blood test? What standards? What symptoms if they are high? Too low?
In people at risk of liver problems or in case of suspicion of certain liver or heart diseases, a dosage of transaminases (ASAT or ALAT) may be prescribed. What does the direct debit consist of? How to interpret the results and what are the solutions for lower your transaminase levels ? What causes transaminases to increase? Answers and advice from Professor Patrick Marcellin, hepatologist at Beaujon Hospital (AP-HP) and President of the APHC (Association for improving the care of patients with chronic liver disease).
Definition: what are transaminases?
Transaminases are enzymes found in body cells, particularly in the muscles and liver. We distinguish two types of transaminases:
- ALT transaminases (or TGP Where SGPT)
- AST transaminases (or TGO Where SGOT)
What are ALT transaminases?
ALT or TGP transaminases (Alanine-Amino-Transferase or SGPTSerum GlutamoPyruvate Transferase) which are mainly found in liver and kidney cells and in small quantities in striated muscles and red blood cells;
What are AST transaminases?
ASAT or TGO transaminases (Aspartate-Amino-Transferase or SGOTSerum GlutamoOxaloacetate Transferase) which are mainly found in striated muscle cells (skeletal and cardiac), red blood cells and liver cells.
What are the normal values of transaminases?
The level of transaminases varies according to gender, age, body temperature and body mass index (BMI). Otherwise, “be aware that transaminase standards may vary slightly depending on the technique used in the medical analysis laboratory“, specifies the hepatologist. These standards are given as an indication, they do not in any way replace the opinion of a health professional.
| ALT (assay at 37°C) | AST (assayed at 37°C) | |
|---|---|---|
| Man | 8 to 45 IU/L | 10 to 40 IU/L |
| Women | 6 to 35 IU/L | 10 to 35 IU/L |
| New born | 5 to 35 IU/L | 20 to 80 IU/L |
| Child (4 to 14 years old) | 10 to 35 IU:L | 10 to 35 IU/L |
Why prescribe a transaminase assay?
In a healthy person, there is no reason to prescribe a blood test for transaminases. In contrast, “in case of suspected illness such as viral hepatitis, myocardial infarction or liver disease* and in people at risk of liver problems (risk of hepatitis B or C, intravenous drug users, obesity, diabetes or family predisposition to hepatitis disease), a dosage of transaminases is recommended. The level of transaminases is proportional to the severity of liver damage, except in chronic liver disease“, recalls the hepatologist.
It is best to be on an empty stomach.
It is preferable to be on an empty stomach and not to have done intense physical activity before taking the blood test, to avoid the risk of haemolysis, destruction of the red blood cells present in the blood. On D-Day, remember to bring your medical prescription, your vital card and health insurance and above all, to report your current treatments. The determination of transaminases consists of a venous blood sample, generally at the bend of the elbow. The collection tube may optionally contain an anticoagulant. The tubes are then examined and give a rate that you must transfer to the prescribing doctor so that he can refer you to additional examinations or prescribe a possible treatment.
A chronic elevation of transaminases is considered when theincrease in transaminases is greater than 1.5 times the upper limit of normal
The results of a blood test are never sufficient to be able to make a diagnosis, regardless of the dosage performed. Only the doctor who will have prescribed it to you will be able to evoke a diagnosis after having compared these results with his interrogation, his clinical examination and the results of possible other examinations. Rest assured: an increase in the level of transaminases does not necessarily reflect an anomaly. However, a chronic elevation of transaminases is considered when theincrease in transaminases is greater than 1.5 times the upper limit of normal, and seen twice for more than 6 months. The ideal is to perform another dosage a few weeks apart. It is also most often necessary to carry out a blood test for hepatic activity including at least the blood test for gamma-GT, albumin and bilirubin.
Elevated transaminases: what causes transaminases to rise?
A high transaminase level is the reflection of cell damage (known in the medical field as cytolysis). “We can also observe an increase in transaminases during the destruction of hepatic cells, and in particular in all liver damage (whether viral, microbial, toxic, drug-induced) and liver cancers, It can also be linked to myocardial infarction, parasitosis, pancreatitis, muscle damage“, explains Professor Marcellin. Taking certain medications (anticonvulsants, oral contraceptives, long-term hepatoxic drugs, certain epileptics) and excessive alcohol consumption can raise transaminase levels. Overweight is also a factor in the increase of transaminases: there is a 10% increase in overweight women and 50% in men. Finally, people over the age of 60 may have higher transaminase levels. In details :
► One increase in transaminases from 2 to 10 times higher normal value may be a sign of infectious viral hepatitis (infectious mononucleosis, varicella-zoster or HIV), other infectious hepatitis such as toxoplasmosis, syphilis, sepsis… or secondary liver damage such as lupus, rheumatoid arthritis…
► One increase in transaminases greater than 10 times the normal value can be a sign of acute viral hepatitis, drug and toxic hepatitis or acute hepatic ischemia linked to cardiac damage such as a heart attack or a heart rhythm disorder
► One prolonged increase (greater than 6 months) transaminases can be a sign of alcoholic involvement such as cirrhosis or hepatitis, steatosis, chronic, drug-induced, toxic or autoimmune viral hepatitis, hemochromatosis, Wilson’s disease, etc.
Low transaminases: the sign of what?
Pregnancy decreases the level of transaminases by an average of 20%. Severe vitamin B6 deficiency can also lower ALT transaminase levels by 20%.
What treatment in case of elevated transaminases?
There is currently no treatment capable of lowering the level of transaminases. Lowering your alcohol consumption, eating a balanced diet and doing regular physical activity, however, can improve your transaminase levels.
Thanks to Professor Patrick Marcellin, hepatologist at Beaujon Hospital (AP-HP) and President of the APHC (Association for improving the care of patients with chronic liver disease).
Source : International Paris Hepatology Conference