Alanine aminotransferase (ALT) is an enzyme found primarily within liver cells, with smaller amounts in the kidneys and other organs. This enzyme plays an important role in the body’s metabolism, converting food into energy. An ALT test is a routine part of blood panels that assesses liver health.
What is ALT SGPT?
ALT, also known as SGPT, is an enzyme vital for liver metabolism. It helps break down proteins, transforming them into energy for the body’s cells. When liver cells are damaged, ALT can leak into the bloodstream, leading to elevated levels in blood tests.
Normal ALT levels typically fall between 7 and 56 units per liter (U/L), though ranges can vary between laboratories. Low ALT levels are uncommon and usually do not indicate a significant health problem, often reflecting a healthy liver or lacking clinical significance on their own.
Why ALT Levels Might Be Low
While low ALT levels are often considered benign, certain underlying conditions can contribute to their decrease. One factor is a deficiency in vitamin B6, also known as pyridoxine. Vitamin B6 acts as a crucial cofactor for the ALT enzyme. Without sufficient vitamin B6, measured ALT levels might appear artificially low. This deficiency can occur in older adults, individuals with liver or kidney damage, and those with alcoholism.
Chronic kidney disease (CKD) can also lead to lower ALT levels. Studies have shown that ALT levels tend to be lower in patients with CKD compared to those with normal kidney function, and these levels can further decline as kidney function deteriorates. Possible reasons for this reduction include vitamin B6 deficiency (common in CKD patients) and hemodilution, where excess fluid dilutes enzyme concentrations.
Paradoxically, severe liver disease, such as advanced cirrhosis, can sometimes result in low or normal ALT levels. In these advanced stages, the liver may be too damaged to produce sufficient ALT. This situation is distinct from earlier stages of liver damage, where ALT levels typically rise due to cell injury. Other factors that may contribute to low ALT include malnutrition, intense exercise, smoking, and hormone therapy.
When to Talk to Your Doctor
A low ALT level is often not a cause for immediate concern and may simply reflect normal liver function. However, consult a healthcare provider if persistently low ALT levels are observed, especially when accompanied by other symptoms. These symptoms might include unexplained fatigue, weakness, nausea, changes in appetite, or cognitive issues.
Consult a doctor if you have pre-existing medical conditions, such as chronic kidney disease, liver disease, or nutrient absorption issues. Your doctor can interpret the ALT results within the broader context of your overall health, medical history, and other relevant blood tests. A comprehensive evaluation by a medical professional provides the most accurate assessment of your health.