Final answer:
A bioconfirmational marker for hepatitis C infection is the presence of hepatitis C viral RNA in the blood.
Step-by-step explanation:
A bioconfirmational marker for hepatitis C infection is the presence of hepatitis C viral RNA in the blood. To confirm a positive test result for hepatitis C, a second, more expensive and time-consuming test is performed to directly test for the presence of viral RNA. Only after the confirmatory test comes back positive can a patient be definitively diagnosed with a hepatitis C infection.