Liver and pancreas
ALAT
A liver enzyme that leaks into the blood when liver cells are damaged; the first test when a liver disorder is suspected.
Everything about this testWhat it measures
ALAT (alanine aminotransferase) is an enzyme found mainly in liver cells, where it helps with the metabolism of proteins. Normally there is little ALAT in the blood. If liver cells are damaged, for example by fat, alcohol, a virus or medicines, ALAT leaks into the blood and the value rises. This often happens before there are any symptoms. According to the Dutch GP guideline (NHG), ALAT is the first and most specific blood test for damage to liver cells.
- Damage to liver cells, whatever the cause (fatty liver, alcohol, viral hepatitis, medicines)
- Chronic liver inflammation due to hepatitis B or C, even without symptoms
- Monitoring of the liver with medicines or substances that can strain the liver, such as anabolic steroids
High
A slightly raised ALAT in someone without symptoms is common and is usually not a serious liver disease. The most common cause is fatty liver due to overweight, diabetes or alcohol. Heavy exercise or strength training in the days before the sample collection, medicines (including high-dose paracetamol, statins, antibiotics), anabolic steroids and herbal preparations can also raise the value temporarily. A strongly raised value, more than ten times the upper limit, fits acute liver inflammation, usually due to a virus, and needs further testing straight away. Symptoms that may go with liver damage: tiredness, pain in the upper right abdomen, dark urine, yellow skin or yellow whites of the eyes.
Low
A low ALAT has no meaning; the value can be very low in healthy people. Only with severe malnutrition or a vitamin B6 deficiency is the value sometimes somewhat lower than expected, but ALAT is not used for that.
If your result is abnormal
With a slightly to moderately raised ALAT without a clear cause, the GP repeats the test after about 4 weeks, usually with the advice not to drink alcohol during that period and after checking medicines and supplements. If the value stays raised, testing for hepatitis B and C and iron overload follows, and usually an ultrasound of the liver. With a value of more than ten times the upper limit or with jaundice, further testing or referral to a gastroenterologist follows straight away.
Reliability
ALAT is sensitive to damage to liver cells but says nothing about the cause; further testing is needed for that. A normal ALAT does not completely rule out liver disease: in liver cirrhosis (scarred liver), a blocked bile duct and some chronic infections, the value can be normal. The Dutch GP guideline (NHG) only attaches meaning to a rise that is present on repeated testing; a single slightly raised value is often temporary.
Limitations
- Heavy exercise or strength training in the 2 to 3 days before the sample collection can raise ALAT, usually together with ASAT and creatine kinase.
- Alcohol in the days before the sample collection, medicines (including paracetamol, statins, anti-epileptic drugs, antibiotics), anabolic steroids and supplements can raise the value.
- Reference values differ per laboratory and are higher for men than for women; a higher body weight gives a higher ALAT on average.
How common is this
A slightly raised ALAT is regularly found in adults who have blood tests without symptoms. Fatty liver is by far the most common cause and, according to the Dutch GP guideline (NHG), occurs in about 1 in 4 adults, and much more often in people with overweight or diabetes. In the Netherlands, about 40,000 people have chronic hepatitis B and about 25,000 have chronic hepatitis C, often without knowing it.
Who is this useful for
Useful with symptoms that fit a liver disorder (tiredness with pain in the upper right abdomen, jaundice, dark urine), with overweight or diabetes and a suspected fatty liver, with long-term heavy alcohol use, when using medicines or anabolic steroids that strain the liver, and with an increased risk of hepatitis B or C. Also suitable for monitoring a previously abnormal value. In healthy adults without risk factors, a chance finding of a slightly raised value is often temporary or harmless and mainly leads to extra testing.
Downsides and risks
- A slightly raised ALAT is often temporary (sport, alcohol, medicines); without a repeat measurement, this can cause unnecessary worry and unnecessary follow-up testing.
- A normal value can give false reassurance in advanced liver damage, where ALAT can fall again.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results