Key facts:

• Any alteration of liver enzymes (especially ALT) is a cause of concern.
• The most common cause of the accidental discovery of elevated ALT is a nonalcoholic fatty liver disease (NAFLD).
• Other causes include alcoholism, viral hepatitis, medications, and immune-mediated liver diseases.
• The normal upper levels of ALT are according to age and weight.
• Children (especially those below 18 months) typically have higher ALT levels.
• Also, males have higher average ALT levels than females.
• Therefore, you must seek medical advice for any ALT levels above the upper limit of normal for your age and gender.
• However, mildly elevated levels don’t often mean serious disease. Don’t be too anxious about such ALT levels. Seek advice to get help with the cause.

When to worry about ALT Levels?

Any deviation from the normal reference ranges of ALT for your age and gender should be investigated.

It is not normal for your ALT levels to be elevated (even mildly) without knowing the cause.

A minor elevation of the ALT levels can cause significant liver damage if continuous for years. So, always seek medical advice whenever you notice any elevation of your ALT levels.

ALT is a liver enzyme that results from the death and rupture of the liver cell (the hepatocyte).

Any increase in ALT levels above the reference range for age and gender means ongoing damage to liver cells. So, you should worry about any Abnormal levels of ALT.

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When to worry about ALT levels (according to your gender and age):

The reference ranges for normal ALT levels also vary from laboratory to laboratory.

Also, some studies suggest that ALT levels may be slightly higher in people with abdominal obesity. So, these three variants (age, gender, and abdominal obesity) should be considered.

Below, the reference range of normal ALT levels by the famous medical laboratory (LabCorp®).

Your doctor should investigate any ALT levels above the above reference ranges.

Should I worry about mild ALT elevations (50 to 90 or 100 U/L)?

Mild elevations of liver enzymes (including ALT) are any elevations that are less than five times the upper limit of normal (ULN).

ALT levels such as 60, 70, 80, 90, or 100 U/L are frequently discovered accidentally during routine laboratory investigations. In addition, mild elevations of ALT are often asymptomatic.

The two most common causes of mildly elevated ALT are nonalcoholic fatty liver diseases (NAFLD) and medications.

Mild elevations of ALT (for example, 50 to 100 U/L) often reflect a chronic liver disease (rather than acute).

Although the damage is not immediate, leaving a mild ALT elevation can cause significant liver damage for enough time.

The time it takes for mildly elevated liver enzymes due to chronic inflammation is often years.

Causes of mild to moderate elevations of ALT levels:

The following diseases can cause mild to moderate elevations of liver enzymes (up to 5 times the upper limit of normal ALT):

• Nonalcoholic fatty liver disease (steatohepatitis).
• Drugs such as recent intake of an anoanorectalgesic or antibiotics.
• Chronic hepatitis C.
• Chronic hepatitisB.
• Liver congestion (in people with heart diseases).
• Malignant infiltration of the liver.
• Hemochromatosis.
• Toxins.
• Autoimmune hepatitis.
• Celiac disease.
• Alcoholic liver injury.
• Liver cirrhosis.
• Wilson’s disease.
• Alpha-1 antitrypsin deficiency.
• Other viruses such as HEV, EBV, and CMV.

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Do mildly elevated ALT levels always mean liver disease?

The two most important liver enzymes are ALT and AST. They are released from damaged liver cells into the blood, where they can be measured.

ALT is more specific as a marker of liver inflammation than ALT, as the liver is its primary source.

AST is not very specific because it is released from other organs (skeletal muscles, brain cells, the heart muscles, and the kidney.

So, ALT is a more specific marker than AST, and even a mild elevation of ALT levels (50 to 100 IU) means the liver is affected.

How will your doctor evaluate your elevated ALT? (in detail):

The following are the expected approach that your doctor will take to search for the cause of elevated ALT.