Evaluation of abnormal liver tests

Area of Science:

• Hepatology
• Clinical Biochemistry
• Diagnostic Medicine

Background:

• Serum liver tests are vital for evaluating hepatic disease but frequently misinterpret hepatocellular damage as impaired liver function.
• The term "liver function tests" is misleading; most assays measure liver cell injury rather than actual liver function.
• True indicators of liver function include albumin synthesis, clotting factor production, and drug metabolism capacity.

Purpose of the Study:

• To clarify the distinction between hepatocellular damage markers and true liver function tests.
• To review patterns of elevated liver enzymes in various liver diseases.
• To present an algorithm for the diagnostic evaluation of abnormal liver test results.

Main Methods:

• Review of common automated liver test panels, including bilirubin, aminotransferases, alkaline phosphatase, and gamma-glutamyl transpeptidase.
• Analysis of diagnostic patterns associated with elevated enzyme values in liver diseases.
• Development of a clinical algorithm for interpreting abnormal liver test results.

Main Results:

• Commonly ordered "liver function tests" primarily reflect hepatocellular damage.
• Specific patterns of elevated enzymes can suggest particular liver diseases, but limitations exist.
• An algorithm is proposed to guide the systematic evaluation of abnormal liver test results.

Conclusions:

• Distinguishing between liver damage markers and true liver function tests is essential for accurate diagnosis.
• Interpreting elevated liver enzymes requires understanding their diagnostic limitations.
• A structured approach, such as the proposed algorithm, can improve the evaluation of patients with abnormal liver tests.