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.
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.
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.
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.
There are many causes of mildly elevated ALT and AST levels. The most common causes are nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease. In NAFLD, the liver has more fatty tissue in it than normal. Regular or heavy alcohol use can also hurt the liver and increase liver enzymes.
10–40 IU/L. High. >36 U/L. >1,000 U/L are very high levels and may be a sign of liver injury or hepatitis. >40 IU/L which may be a sign of liver inflammation.
Elevated liver enzymes might be discovered during routine blood testing. In most cases, liver enzyme levels are only mildly and temporarily elevated. Most of the time, elevated liver enzymes don't signal a chronic, serious liver problem.
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.
AST is usually higher than ALT and both enzymes peak in the first 24 hours after admission. After peaking, both levels fall rapidly; AST faster than ALT. Peak ALT levels bear no relationship to prognosis and may fall with worsening of the patients condition.
Aspartate Transaminase (AST): Very high levels of AST (more than 10 times normal) are usually due to Acute Hepatitis, sometimes due to a viral infection. With acute Hepatitis, AST levels usually stay high for about 1-2 months but can take as long as 3-6 months to return to normal.
Avoid drinking alcohol until your AST levels return to the normal range, even if the cause is not alcohol-related [34]. If you are overweight, losing weight may improve your liver health and help reduce AST [35]. Some drugs or supplements can damage the liver, leading to high AST levels.
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.
Aspartate transaminase (AST).
AST is an enzyme that helps metabolize amino acids. Like ALT, AST is normally present in blood at low levels. An increase in AST levels may indicate liver damage, disease or muscle damage.
Laboratory abnormalities often are the only sign of non-alcoholic fatty liver disease. The most common abnormal laboratory test results are elevated alanine transaminase (ALT) and aspartate transaminase (AST), usually one to four times the upper limits of normal.
On the basis of this meta-analysis, we confirmed an improvement in ALT and AST through fasting compared with a non-fasting control group. This seems to be related to a decrease in BW and a reduction in BMI.
Conclusion: ALT/AST ratio reversal alone has a high sensitivity and the combined effect of these two parameters increases the specificity as compared to either of the two alone. The high positive predictive value here shows that almost all the patients with reversed ratio and prolonged PT will have cirrhosis.
What ALT level is considered high? The upper limit of normal for ALT is 55 IU/L. When an ALT level is double to triple the upper limit of normal, it is considered mildly elevated. Severely elevated ALT levels found in liver disease are often 50 times the upper limit of normal.
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.
In general, high levels of ALT may be a sign of liver damage from hepatitis, infection, cirrhosis, liver cancer, or other liver diseases. The damage may also be from a lack of blood flow to the liver or certain medicines or poisons.
Many medications can cause increases in AST, such as acetaminophen, NSAIDs, ACE inhibitors, nicotinic acid, INH, sulfonamides, erythromycin, and antifungal agents such as griseofulvin and fluconazole. In acetaminophen overdose, transaminase levels greater than 10,000 IU/L are also noted.
A high ALT level is usually a sign of some type of liver issue. It's important to work with your doctor to find the underlying cause of your elevated ALT, even if you don't have any symptoms. Lowering your ALT will require treating the cause, but certain dietary changes can help.
Normal Results
The normal range is 8 to 33 U/L. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your health care provider about the meaning of your specific test results.