Significance of the hepatitis C virus (HCV) core antigen as an alternative plasma marker of active HCV infection.
OBJECTIVE
To evaluate the role of core antigen (Ortho trak-C assay) as a marker of active HCV infection in comparison to HCV RNA as detected by reverse transcription polymerase chain reaction (RT-PCR).


METHODS
This evaluation was carried out during January 2000 to December 2003 in HCV infected individuals who were treatment naomicronve or were on anti-viral therapy. Additionally, sequential plasma samples from patients on clinical follow-up were included in this study. A total of 167 samples from 61 patients were tested by trak-C and RT-PCR. HCV RNA detection was achieved by a RT-PCR. Trak-C assay results were also compared in a limited proportion of these samples with known HCV viral load and genotype.


RESULTS
Of 167 samples tested, 56.9% were RNA positive and 43.1% were RNA negative while 50.3% were trak-C positive and 49.7% were trak-C negative, yielding a sensitivity of 85.3% and a specificity of 95.8% for the trak-C assay (Kappa co-efficient = 0.8). The concentration of HCVcAg and HCV RNA showed significant correlation (n=38, r=0.334, P =0.04). The trak-C assay detected the most prevalent HCV genotypes in India without significant difference (P =0.335). The difference between mean absorbance values of HCV RNA positive samples compared to HCV RNA negative samples in the trak-C assay was highly significant (P < 0.000). Qualitative results of trak-C assay and RT-PCR were comparable in 93% of follow-up samples.


CONCLUSIONS
Trak-C assay can be recommended for confirmation of HCV infection and follow-up in laboratories with resource-poor facilities.
Daniel
H D J
HD
Department of Clinical Virology, Christian Medical College, Vellore, Tamil Nadu, India.
Vivekanandan
P
P
Raghuraman
S
S
Sridharan
G
G
Chandy
G M
GM
Abraham
P
P
D016174:Hepacivirus / Q000235:genetics / Q000276:immunology*; D006526:Hepatitis C / Q000097:blood* / Q000175:diagnosis; D018936:Hepatitis C Antigens / Q000097:blood*; D007194:India; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D018936:Hepatitis C Antigens; D012367:RNA, Viral