THE HCV-BDNA PROBE METHOD FOR MEASUREMENT OF HCV-RNA COUNTS BY HCV GENOTYPE

HCV-RNA counts have been determined previously by using the reverse tr anscription (RT)-competitive polymerase chain reaction (PCR) method. R ecently, the HCV-branched DNA (HCV-bDNA) probe method, an application of hybridization technology, was developed, and it made an easy measur ement of HCV-RNA counts possible. In the present study, we investigate d the relationship between the measurements using the RT-competitive P CR method and those using the HCV-bDNA probe method for each HCV genot ype. Positive rates for each HCV genotype measured by the HCV-bDNA pro be method were 88. 1 % for type II, and 66.6% for the sum of the rates in type III and type IV. The rate for type II was significantly highe r (P = 0.029) than the others. HCV-RNA counts in patients, measured by the HCV-bDNA probe method and the RT-competitive PCR, were plotted on a log-log graph, and slopes for each genotype were compared. Results showed that the slope for type II patients was the largest, i.e., y = 0.236x + 5.4, and that for type III was the smallest, i.e., y = 0.103x + 5.3. It should be noted that patients with high HCV-RNA counts, in using the RT-competitive PCR method, tended to have lower counts in us ing the HCV-bDNA probe method.