Although levels of ALT and AST can be extremely elevated (exceeding 2,000 U per L in cases of hepatocyte injury and necrosis related to drugs, toxins, ischemia, and hepatitis), elevations less than five times the upper limit of normal (i.e., about 250 U per L and below) are much more common in primary care medicine.
An AST/ALT ratio higher than one (where the AST is higher than ALT) means you may have cirrhosis. An AST/ALT ratio higher than 2:1 (where the AST is more than twice as high as the ALT) is a sign of alcoholic liver disease.
An ALT test result of >100 IU/l is a clear indicator of serious liver disease, but a mildly elevated ALT result (30–100 IU/l) is often ascribed to the use of medication (for example statins) or alcohol, obesity, or, for lower ALT levels (<50 IU/l), considered as part of the normal distribution of test results.
Typically the range for normal AST is reported between 10 to 40 units per liter and ALT between 7 to 56 units per liter. Mild elevations are generally considered to be 2-3 times higher than the normal range. In some conditions, these enzymes can be severely elevated, in the 1000s range.
Elevated values up to 300 U/L are considered nonspecific. Marked elevations of ALT levels greater than 500 U/L observed most often in persons with diseases that affect primarily hepatocytes such as viral hepatitis, ischemic liver injury (shock liver) and toxin-induced liver damage.
If you have high levels of AST and/or ALT, it may mean that you have some type of liver damage. You may also have an AST test as part of a group of liver function tests that measure ALT, and other enzymes, proteins, and substances in the liver.
The AST is typically in the 100 to 200 IU/L range, even in severe disease, and the ALT level may be normal, even in severe cases. The AST level is higher than the ALT level, and the ratio is greater than 2:1 in 70% of patients. A ratio greater than 3 is strongly indicative of alcoholic hepatitis.
Standard medical education dictates that the vast majority of cases of an alanine aminotransferase (ALT) level >1,000 IU/l will be due to acute ischaemia, acute drug-induced liver injury (DILI) (usually paracetamol) or acute viral hepatitis.
A high AST level often means there is some liver damage, but it is not necessarily caused by hepatitis C. A high AST with a normal ALT may mean that the AST is coming from a different part of the body. It is important to realize that the AST level in most patients with hepatitis C goes up and down.
ALT levels greater than 15 times the normal range indicate severe acute liver cell injury and evaluation should be initiated immediately. The differential diagnosis for patients with severe acute liver injury (ALT levels >15 times the normal range) is relatively limited.
If they are constantly in the 50 to 200 range we term the hepatitis B infection active. ALT's range from 0 up to 3000 or so in many acute hepatitis cases. They change with every meal so it is important not to panic if they go from 20 to 45 after a few months. All scores below 45 indicate a perfectly healthy score.
Usually, the upper limit of ALT is 35 - 40 U/L. Moderate increase in ALT (such as 70 U/L) is seen in chronic hepatitis, chronic obstruction of bile ducts, heart damage, alcohol abuse, liver tumor, skeletal muscle damage. In any acute liver conditions, ALT is much more elevated.
However, patients with nonalcoholic fatty liver disease may have normal transaminase levels. The ratio of AST/ALT usually is less than 1 (in alcoholic liver disease, this ratio typically will be greater than 2) but may increase as the severity of the liver damage increases.
ALT is located primarily in liver and kidney, with lesser amounts in heart and skeletal muscle. Increased ALT activity is more specific for liver damage than increased aspartate aminotransferase (AST) activity.
Abnormal liver function test with raised alanine aminotransferase (ALT) and raised aspartate aminotransferase (AST) are commonly seen in primary care setting. Chronic alcohol consumption, drugs, non-alcoholic steatohepatitis (NASH) and chronic viral hepatitis are common causes associated with raised ALT and AST.
High liver enzyme levels may be temporary, or they may be a sign of a medical condition like hepatitis or liver disease.
Most causes of liver cell injury are associated with a greater increase in ALT than AST, but an AST/ALT ratio of 2:1 or greater is suggestive of alcoholic liver disease, particularly in the setting of an elevated gamma-glutamyl transferase.
Extremely high ALT levels (often 3,000 U/L or more) indicate toxic impairment of the liver by a drug or poison, or a condition that decreases blood flow through the liver, destroying cells (ischemia).
THE FATTY LIVER AND THE AST:ALT RATIO
A normal AST:ALT ratio should be <1. In patients with alcoholic liver disease, the AST:ALT ratio is >1 in 92% of patients, and >2 in 70%. AST:ALT scores >2 are, therefore, strongly suggestive of alcoholic liver disease and scores <1 more suggestive of NAFLD/NASH.
avoiding processed foods, especially fried foods and foods high in sugar, fat, and salt. avoiding raw or undercooked shellfish. increasing dietary fiber by eating whole grains, fruit, and vegetables.
Elevated AST and ALT levels may indicate liver injury. These are the enzymes that are most commonly released into your bloodstream when your liver is stressed. If both are elevated equally, it indicates a nonalcoholic type of injury, which may include infection or other toxins.
ALT test results may help tell the difference between damage from acute (sudden) liver problems and chronic (long-term) liver problems. But the amount of ALT in your blood isn't related to how much your liver may be damaged. ALT used to be called SGPT, which stands for serum glutamic-pyruvic transaminase.