Primary Care Coding Alert

Question: What is the correct diagnosis code to use when a patient’s aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels are elevated according to the results of a comprehensive metabolic panel (CMP)? Should I use R74.8, R94.5, or K76.89?

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Answer: A CMP (CPT^® 80053) tests for levels of 14 different chemicals in the blood: albumin, total bilirubin, total calcium, carbon dioxide (bicarbonate), chloride, creatinine, glucose, alkaline phosphatase, potassium, total protein, sodium, ALT, AST, and urea nitrogen.

A diagnosis of R94.5 (Abnormal results of liver function studies) would not apply in this case, because a CMP is not a liver function study. Although elevated AST and ALT may be associated with liver damage or disease, you would need the abnormal findings from an actual liver function study, rather than a CMP, to report R94.5.

A diagnosis of R74.8 (Abnormal levels of other serum enzymes) would also not apply, as the diagnosis applies to abnormal levels of acid phosphatase, alkaline phosphatase, amylase, or triacylglycerol lipase. While 80053 includes alkaline phosphatase, you do not state that the test indicated elevated levels. More, the AST and ALT, which are elevated, are not included under R74.8.

Similarly, K76.89 (Other specified diseases of liver) is incorrect, as the diagnosis applies to other specified liver conditions, such as a simple liver cyst, focal nodular hyperplasia of liver, and hepatoptosis. In this case, you do not have a specified disease of the liver, just elevated levels of ALT and AST. As previously noted, they may be associated with liver damage or disease, but that would not be determined by the CMP.

In fact, the diagnosis code that most accurately reports elevated AST and ALT levels is R74.0 (Nonspecific elevation of levels of transaminase and lactic acid dehydrogenase [LDH]).