In a patient with elevated liver transaminases, what is the most likely cause if Hepatitis A and B serologies are inconclusive?

The presence of elevated liver transaminases without conclusive serologies for Hepatitis A and B suggests a need to consider other common conditions that can lead to liver enzyme abnormalities. Fatty liver disease, particularly non-alcoholic fatty liver disease (NAFLD), is one of the most prevalent causes of elevated liver enzymes in individuals, especially in the context of conditions like obesity, insulin resistance, or metabolic syndrome.

In the absence of clear markers for Hepatitis A or B, the likelihood of fatty liver disease increases due to its strong association with elevated liver enzymes. The condition is often asymptomatic and can be revealed through imaging or liver biopsies if needed. Moreover, it commonly occurs in patients who may not consume significant alcohol, thus aligning with the scenario presented where other causes such as alcoholic liver disease or chronic hepatitis B are less likely or do not fit the serology findings.

Overall, fatty liver disease emerges as a prominent differential diagnosis in this context, highlighting its role as a major cause of liver enzyme elevation when viral hepatitis serologies are not definitive.