High ALT (SGPT)
ALT is an enzyme that sits mostly inside liver cells. When they’re irritated or damaged, ALT leaks into the blood. Its old name is SGPT, so if your report says SGPT, it’s the same test.
Quick answer: ALT (also called SGPT) above about 40 U/L in men or 35 U/L in women is raised. Fatty liver is the commonest cause, followed by alcohol, medicines and supplements, hard exercise and viral hepatitis. Even mild rises deserve a cause. ALT over 10 times the upper limit usually means acute hepatitis and needs prompt review.
What the test measures
Alanine aminotransferase (ALT), once called serum glutamic-pyruvic transaminase (SGPT), is part of your liver function tests (LFTs). It’s the most liver-specific of the liver enzymes. A high ALT means liver cells are irritated, but the level doesn’t always match how serious the cause is.
Typical adult ranges
- Men: 5–40 U/L
- Women: 5–35 U/L
- These are the common Australian ranges. U/L and IU/L are the same number. Some experts, including the American College of Gastroenterology, suggest healthy upper limits closer to 29–33 U/L for men and 19–25 U/L for women.
The other liver tests
- AST (SGOT): also found in muscle and heart, so it rises with exercise and muscle injury. AST more than twice ALT is a classic pattern in alcohol-related liver disease.
- GGT: raised by alcohol, fatty liver, some medicines and bile duct problems.
- ALP: comes from bile ducts and bone. Raised with bile duct blockage, and normally higher in growing teenagers and pregnancy.
- Bilirubin: high levels cause jaundice. A mildly raised bilirubin with otherwise normal tests is often Gilbert’s syndrome, which is harmless.
- Albumin and INR: show how well the liver is making proteins. These fall late in serious liver disease.
What a high result usually means
Common causes:
- Fatty liver (MASLD), linked with weight, type 2 diabetes and high triglycerides. The commonest cause. See fatty liver.
- Alcohol.
- Medicines and supplements: paracetamol above the recommended dose, statins (usually mild), some antibiotics such as amoxicillin-clavulanate, methotrexate, and herbal products such as green tea extract and turmeric supplements.
- Hard exercise or muscle injury, for several days afterwards.
- Viral hepatitis: hepatitis B and C (long-term), or a recent infection such as glandular fever.
Less common but important:
- Haemochromatosis (see high ferritin), autoimmune hepatitis, coeliac disease and thyroid disease.
- Wilson disease (in younger people) and alpha-1 antitrypsin deficiency.
- Very high ALT (over 10 times normal): acute viral hepatitis (A, B or E), paracetamol overdose, drug reactions, a passing gallstone, or a sudden drop in blood flow to the liver.
Symptoms
Usually none. Some people have tiredness or discomfort under the right ribs. Yellow skin or eyes, dark urine, pale bowel motions and itch suggest a more serious problem.
What happens next
- Look for the cause, even if the rise is mild. UK guidance advises a liver screen rather than simply repeating the test, unless a short-lived cause (like a recent hard workout) is likely.
- Usual tests: liver ultrasound, hepatitis B and C, ferritin and transferrin saturation, liver autoantibodies and immunoglobulins; sometimes coeliac and thyroid tests.
- Review alcohol, medicines and supplements, including anything from a health-food shop or online.
- If fatty liver is likely, a FIB-4 score (from your age, ALT, AST and platelets) or a FibroScan estimates liver scarring.
- Referral to a liver specialist if scarring is likely, the cause is unclear, or ALT stays high.
See a doctor the same day for yellow skin or eyes, dark urine with pale bowel motions, or an ALT over 10 times the upper limit (roughly 400 U/L or more) if you feel unwell. Get urgent help (000 in Australia, or your local emergency number) for confusion or drowsiness, vomiting blood or black bowel motions, or if you’ve taken more paracetamol than the recommended dose, even if you feel fine.
Practise reading results. Play Panelysis, the daily blood-test puzzle: a fictional patient, a real-looking panel, three guesses. More in medical games.
Common questions
What does SGPT high mean?
SGPT is the old name for ALT, so a high SGPT means the same as a high ALT: liver cells are irritated. The commonest causes are fatty liver, alcohol and medicines or supplements. Your doctor will look for the cause with a few more tests.
Is an ALT of 60 dangerous?
It’s mildly raised and not dangerous in itself, but it’s worth finding out why. Fatty liver and alcohol are the usual causes. Your GP will usually check for hepatitis, iron overload and other causes, and may arrange a liver ultrasound.
Can exercise raise ALT?
Yes. Heavy weights, long runs or a muscle injury can raise ALT and especially AST for several days. Avoid hard workouts for a few days before a repeat test so the result isn’t muddied.
Which medicines and supplements raise ALT?
Common ones include paracetamol above the recommended dose, statins (usually a small rise), some antibiotics such as amoxicillin-clavulanate, methotrexate, and some herbal products such as green tea extract and turmeric supplements. Never stop a prescribed medicine without talking to your doctor.
How can I lower my ALT?
Treat the cause. For fatty liver, losing 7–10% of your body weight often brings ALT down and can reverse liver fat. Cutting back on alcohol and stopping unnecessary supplements also help.
What’s the difference between ALT and AST?
Both are liver enzymes, but AST is also found in muscle and heart, so ALT is more specific to the liver. AST more than twice ALT is a classic clue to alcohol-related liver disease.
Evidence and more information
- Pathology Tests Explained (RCPA): Alanine aminotransferase (ALT)
- Pathology Tests Explained (RCPA): Liver function tests
- Newsome et al, Gut 2018: British Society of Gastroenterology guideline on abnormal liver blood tests
- Kwo, Cohen and Lim, American Journal of Gastroenterology 2017: ACG guideline on abnormal liver chemistries
maladywise.com/blood-tests/high-alt/