[Correlation between signal/cutoff ratios of anti-HCV enzyme immunoassay (EIA) and their true positivity in blood donors].
OBJECTIVE
To evaluate the correlation between signal/cutoff (S/CO) ratios of anti-HCV EIA and their true positivity for determining the predictive value of S/CO ratios.


METHODS
One hundred and fifty-nine samples of blood from donors positive for anti-HCV at the initial screening were collected from Beijing, Guangzhou, Hangzhou, Kunming and Urumchi. All the samples were retested by Ortho and 6 Chinese domestic anti-HCV EIA kits in duplicate, and detected for HCV RNA (NAT) using Chiron Procleix HIV/HCV system (transcription mediated amplification, TMA). The HCV RNA negative samples were further tested for anti-HCV by Chiron RIBA 3.0. Either NAT or RIBA positive samples were interpreted as the true positive.


RESULTS
All 7 anti-HCV EIA kits had a significant correlation between S/CO ratios and true positivity. The S/CO ratio of Ortho > or = 3.8 predicted the true positivity in 96.1% of the samples tested. The S/CO ratios of BGI-GBI, GWK, SABC, KHB, InTec, and Wantai were > or = 7.0, > or = 10.0, > or = 6.0, > or = 10.0, > or = 8.6, > or = 14.0 and predicted 96.1%, 96.1%, 97.3%, 96.0%, 96.1%, 96.0% of the true positivity, respectively.


CONCLUSIONS
The S/CO ratios of anti-HCV EIA kits are associated with the true positivity. S/CO ratios of Ortho, BGI-GBI, GWK, SABC, KHB, InTec and Wantai predicting > or = 95% true positivity are > or = 3.8, > or = 7.0, > or = 10.0, > or = 6.0, > or = 1 0.0, > or = 8.6 and > or = 14.0, respectively.
Ren
Fu-Rong
FR
Beijing Red Cross Blood Center, Beijing 100088, China.
Gong
Xiao-Yan
XY
Li
Jing-Jing
JJ
Lü
Qiu-Shuang
QS
Liu
Chang-Li
CL
Zhuang
Hui
H
Shan
Hua
H
Wang
Jing-Xing
JX
D001782:Blood Donors; D016174:Hepacivirus / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity
D011933:Reagent Kits, Diagnostic