ALT and AST Enzyme Levels in Chronic Kidney Disease Patients Undergoing Hemodialysis

Abstract

Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were commonly used as indicators of liver function. In patients with chronic kidney disease (CKD), particularly those undergoing hemodialysis (HD), levels of these enzymes were often found to be lower than in non-HD patients. This literature review aimed to examine changes in AST and ALT levels among CKD patients undergoing HD. Articles published between 2015 and 2025 were identified through Google Scholar and PubMed using the keywords "ALT AND AST AND Chronic Kidney Disease AND Hemodialysis." A total of nine studies met the inclusion criteria and were analyzed. Overall, AST and ALT levels were found to be consistently lower in HD patients compared with non-HD patients. Enzyme levels tended to increase following dialysis sessions, a change that was attributed to hemoconcentration and the removal of circulating enzyme inhibitors during the dialysis process. However, variation was observed across studies, which was linked to differences in dialysis protocols, timing of blood sampling, and patients' clinical conditions. These findings indicated that reduced liver enzyme levels in HD patients did not necessarily reflect normal liver function, but rather reflected dialysis-related factors and nutritional deficiencies commonly seen in this population. It was concluded that interpretation of liver function tests in CKD patients undergoing HD required careful consideration of dialysis-related variables and individual patient characteristics