Prognostic significance of hepatitis C virus RNA detection by transcription-mediated amplification with negative polymerase chain reaction during therapy with peginterferon α and ribavirin

The lower limit of detection of most polymerase chain reaction (PCR) assays for hepatitis C virus (HCV) RNA is 50 IU/ml, compared to 5 IU/ml for the transcription-mediated amplification (TMA) method. We retrospectively reviewed 57 patients to assess the predictive value of a positive TMA in the setting of a negative PCR during antiviral therapy. Patients were divided into (1) PCR-/TMA+ (discordant; n = 21) and (2) PCR-/TMA-(concordant; n = 36). Sustained virologic response (SVR) was decreased in the discordant group (48% vs. 75%; P= 0.04). In discordant patients, SVR was more frequent in patients who had one positive TMA than in those who had two or more positive TMAs or one positive TMA and recurrent HCV RNA detectability by PCR during treatment (78% vs. 25%; P = 0.03). Breakthrough occurred more frequently in discordant patients (24% vs. 3%; P = 0.02). A positive TMA on two or more occasions in patients who have become PCR-negative on therapy indicates a high likelihood of treatment failure.