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ALT (SGPT)

ALT (alanine aminotransferase), also called SGPT, is an enzyme found mainly inside liver cells. When liver cells are irritated or damaged, ALT leaks into the blood.

Normal range (adults)
Men 7–56 U/L · Women 7–45 U/L
Sample
Blood
Fasting
Not usually needed
Also called
ALT, SGPT, Alanine Aminotransferase, Alanine Transaminase, GPT, Serum GPT, ALAT

ALT normal range

Group U/LSame unit in all countries
Men7–56
Women7–45

Ranges vary slightly between laboratories. The range printed on your own report is the one to go by.

Why is the ALT test done?

It is the most liver-specific enzyme in the liver function test, used to detect fatty liver, hepatitis and medicine side effects.

What does a high ALT level mean?

A high ALT means liver cells are under stress or being damaged. Mild rises (up to 2 to 3 times normal) are very common with fatty liver; very high values suggest hepatitis or medicine or toxin injury.

Common causes

  • Fatty liver (linked to overweight, diabetes and high triglycerides)
  • Viral hepatitis B or C, or acute hepatitis A or E
  • Alcohol
  • Medicines such as paracetamol overuse, some antibiotics, anti-TB drugs and statins
  • Herbal or bodybuilding supplements
  • Heavy exercise in the days before the test

Diet and lifestyle tips

  • Avoid alcohol completely until your ALT normalises
  • Lose 5 to 10% of your body weight if overweight; this can reverse fatty liver
  • Cut sugar, sweet drinks, white rice, bread and fried foods
  • Eat vegetables, fruit, whole grains, legumes, olive oil and fish
  • Black coffee without sugar (1 to 2 cups a day) is linked to healthier liver enzymes
  • Do not take extra painkillers, herbal remedies or supplements without advice

What does a low ALT level mean?

A low ALT is not usually a concern.

Common causes

  • Normal variation
  • Vitamin B6 deficiency (rarely)

Diet and lifestyle tips

  • No action needed

When should you see a doctor?

See a doctor if ALT stays high on a repeat test after 4 to 6 weeks, or is more than 3 times the upper limit. Seek urgent care for yellow eyes, dark urine or severe abdominal pain.

Last updated

This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.