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.
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.
Your ALT level is considered high if it exceeds the normal range of 0 to 44 IU/L. Some laboratories may present a slightly different reference interval, but a test result of 55 IU/L or above could indicate liver problems.
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.
The alanine aminotransferase (ALT) is a specific marker for liver inflammation and is typically elevated in individuals with a fatty liver. If your ALT test results are elevated, your doctor may order additional blood tests to check for other conditions including viral hepatitis.
Alanine aminotransferase (ALT) is a liver enzyme, and high levels can indicate liver damage. Taking steps to lower ALT levels can help the liver recover. Lifestyle changes, such as a healthful diet and regular exercise, can all help to lower ALT levels.
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.
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.
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.
Normal Results
The normal range is 4 to 36 U/L. Normal value ranges may vary slightly among different laboratories.
Article Sections. Mild, asymptomatic elevations (less than five times the upper limit of normal) of alanine transaminase and aspartate transaminase levels are common in primary care. It is estimated that approximately 10% of the U.S. population has elevated transaminase 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.
In healthy individuals, ALT levels can vary 10 to 30% from one day to the next. ALT levels can fluctuate 45% during a single day, with highest levels occurring in the afternoon and lowest levels at night. A high body mass index can increase ALT levels by 40 to 50%. Reference range is 14 - 63 IU/L.
Higher consumption of fast foods (> 11.39% kcal/week) was associated with elevated ALT to AST ratio (OR: 3.27; 95% CI: 1.90–5.63) and elevated ALT (OR: 2.74; 95% CI: 1.57–4.76).
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 low level of ALT in the blood has no clinical significance. An abnormally high level generally indicates that the liver cells are damaged and releasing their contents into the bloodstream. High ALT levels (300 units per litre (U/L) or more) are often caused by acute viral hepatitis.
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.
ALT is considered to be the most liver-specific enzyme. ALT is also produced by cardiac muscle, skeletal muscle, and the kidneys.
Generally speaking, a normal AST level for adults is: 8 to 48 IU/L. A normal ALT level for adults is 7 to 55 IU/L. The high end of the reference range is referred to as the upper limit of normal (ULN). This number is used to establish how elevated your liver enzymes are.
There is no consensus on cutoff point and maximum normal concentration of ALT, and a broad value range, between 26 and 66 IU/L, has been suggested in different studies[37]. Some studies have shown that risk of NAFLD increases as ALT rises to more than 19 and 30 in women and men, respectively.