Liver Enzymes: A Silent Warning Sign for Health

According to Saednews, medical reports, the most sensitive and widely used diagnostic liver enzymes are aminotransferases. These include aspartate aminotransferase (AST, also known as SGOT) and alanine aminotransferase (ALT, also known as SGPT).

Under normal conditions, these enzymes are located inside liver cells. When the liver is damaged, its cells release these enzymes into the bloodstream. Therefore, elevated levels of these enzymes in blood tests are an indicator of liver injury.

Aminotransferases catalyze chemical reactions within cells by transferring an amino group from a donor molecule to an acceptor molecule. This is why they are called “aminotransferases.” Another common term for these enzymes is “transaminases.”

Aspartate aminotransferase (AST) is also referred to as serum glutamic-oxaloacetic transaminase (SGOT), while alanine aminotransferase (ALT) is known as serum glutamic-pyruvic transaminase (SGPT). In summary:
SGOT = AST and SGPT = ALT

Distribution of AST and ALT in the body

AST is naturally present in various tissues, including the liver, heart, muscles, kidneys, and brain. When any of these tissues are damaged, AST is released into the bloodstream. For example, its levels may rise during heart attacks or muscle disorders.

In contrast, ALT is primarily found in the liver. Although it is not exclusively present there, the liver contains the highest concentration of this enzyme. Because ALT is more liver-specific, it is considered a more accurate marker of liver damage.

Normal reference ranges (may vary by laboratory)

• ALT: ≤ 34 IU/L (women), ≤ 52 IU/L (men)

• AST: ≤ 34 IU/L (women), ≤ 40 IU/L (men)

• ALP (Alkaline phosphatase): 20–140 IU/L (both genders)

• GGT (Gamma-glutamyl transpeptidase): 5–55 IU/L (women), 15–85 IU/L (men)

These ranges are approximate and may differ slightly depending on the laboratory.

Elevated liver enzymes and what they mean

Liver enzyme elevations are often detected during routine blood tests. In most cases, these increases are mild and temporary and do not indicate a severe or chronic liver disease.

Since these enzymes normally function inside liver cells, only small amounts are found in the bloodstream. However, when liver cells are damaged, they break down and release enzymes into the blood.

Doctors interpret these changes alongside other physical examinations and diagnostic tests, not just blood results alone.

Important liver enzymes commonly assessed

1. Alanine aminotransferase (ALT)

2. Aspartate aminotransferase (AST)

Symptoms and warning signs of liver disorders

Liver diseases often do not show obvious early symptoms and are frequently discovered during routine checkups or imaging tests such as ultrasound.

Possible symptoms include:

• Fatigue and general weakness

• Upper abdominal discomfort

• Loss of appetite

• Nausea

• Enlarged liver

• Yellowing of the skin, eyes, and nails (jaundice)

• Sudden weight loss

• Nose or gum bleeding

• Vomiting or nausea

Fat accumulation in the liver may also cause weakness, poor appetite, and abdominal discomfort.

Causes of liver disease

Common causes of liver disorders include:

• Hepatitis viruses (A, B, and C)

• Excessive alcohol consumption

• Overuse of painkillers and medications

Severe liver damage can disrupt normal blood flow through the liver, causing blood to be redirected into other vessels. This may lead to complications such as blood in vomit or stool due to gastrointestinal bleeding.

Conclusion

Liver enzymes such as AST and ALT are essential markers for assessing liver health. While mild elevations are often temporary, persistent or significant increases require medical evaluation to identify underlying causes and prevent potential liver damage.