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Laboratory Testing for Hepatitis C



Interpretation of Laboratory Test Results for HCV Infection

Slide 13

April 2008

Now quantitative molecular tests are used for similar indications as those for qualitative tests. However, they have the added advantage of monitoring precise response to antiviral therapy using a quantitative result.

The desirable responses to treatment are indicated here for treatment of Hepatitis C chronic infection, the current state of mgmt requires determining rapid virologic response which is measured at 4 weeks into initiation of treatment. The desirable response is at least 100-fold or 2 log decrease in the serum HCV RNA from the baseline.

Subsequent responses are measured at 12 weeks, which is known as early virologic response. End of treatment response occurs at 24 or 48 weeks depending on the duration of treatment decided by the provider. Finally, six months after the end of treatment which is known as sustained virologic response. The desirable responses at these three points are undetectable HCV RNA levels.

These assays differ in their limits of quantification. There is currently one FDA-approved assay in the US, and that is the VERSANT (name) form Siemens Healthcare Diagnostics which has a lower limit of quantification at 615IU. The other three assays indicated here are either analyte specific reagent (ASR) or are research-use only assays. Note that the real-time RT-PCR assays, such as Taq Man HCV RNA and the Abbott Molecular ASR, have quite good lower limits of quant detection at 10-25 IU/mL.

Interpretation

 


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