Primary Care Lab Values Cheat Sheet

For adults who are overweight or obese and undergo screening for type 2 diabetes, guidelines recommend repeating the screening at least every three years if the initial results are normal. This patient's hemoglobin A1c is 5.2%, which is well within the normal range. Repeating the test in six months, one year, or two years is unnecessary and increases healthcare costs without clinical benefit, assuming his risk profile and clinical status remain stable. Routine clinical monitoring should continue, but formal screening is safely deferred for three years.

A positive anti-HCV antibody indicates prior exposure to the hepatitis C virus but cannot differentiate between an active chronic infection and a past resolved infection. Therefore, ordering a quantitative HCV RNA test is the essential next step to confirm current viral replication. Option A is incorrect because normal transaminases do not rule out active hepatitis C; many patients with chronic infection maintain normal liver enzymes. Option B is premature and overly invasive before confirming active viremia and considering non-invasive fibrosis staging. Option D is incorrect because direct-acting antiviral therapy should never be initiated based solely on an antibody test without confirming the presence of viral RNA.

The patient's presentation and laboratory results strongly support an acute hepatitis B infection. The presence of surface antigen indicates an active infection, while the positive core IgM antibody specifically confirms the acute phase of the illness. Furthermore, an ALT level exceeding 1000 U/L is a classic hallmark of acute viral hepatitis rather than a chronic state. Option B is incorrect because chronic infection would present with core IgG antibodies rather than IgM, and transaminases are typically much lower. Option C is incorrect because a resolved infection would show negative surface antigen and positive surface antibodies. Option D is incorrect because vaccine-induced immunity only presents with positive surface antibodies, lacking both surface antigen and core antibodies.