Evaluation of a transcription-mediated amplification-based HCV and HIV-1 RNA duplex assay for screening individual blood donations: a comparison with a minipool testing system.
BACKGROUND
NAT was introduced for HCV RNA in 1999 to screen blood donations and improve the safety of the blood supply.


METHODS
The performance of a NAT multiplex for HCV and HIV-1 RNA based on transcription-mediated amplification (TMA) was assessed with various sensitivity panels and by screening 50,000 serologically unscreened, first-time donor plasma samples. Results were compared with a routine NAT screening for HCV RNA by RT-PCR in pools of 96 plasma samples.


RESULTS
The TMA multiplex 95 percent sensitivity ranged between 22 and 54 IU per mL for HIV-1 and 15 and 20 IU per mL for HCV RNA. The rate of test failure was 8.6 percent but decreased to 4.7 percent when results of two critical periods of equipment malfunction were excluded. Test failure was related to human error, minute control contamination, and insufficient mixing of reagents at the extraction stage. All 31 repeatedly reactive samples (0.06%) were seropositive for HCV (29) or HIV-1 (2) and contained RNA detectable by discriminatory TMA and confirmatory RT-PCR, indicating 100 percent specificity. A direct comparison of TMA in individual samples and RT-PCR in plasma pools was possible on 27 HCV RNA-containing samples. Twenty-six samples were detected in plasma pools; the lack of detection of 1 sample was due to an identification error at the pooling stage.


CONCLUSIONS
The HCV and HIV-1 multiplex NAT had high specificity and sensitivity.
Candotti
Daniel
D
National Blood Service, East Anglia Center, London, UK. dc241@cam.ac.uk
Richetin
Aline
A
Cant
Barbara
B
Temple
Jillian
J
Sims
Cate
C
Reeves
Ian
I
Barbara
John A J
JA
Allain
Jean-Pierre
JP
D001483:Base Sequence; D001782:Blood Donors; D015658:HIV Infections / Q000175:diagnosis; D015497:HIV-1 / Q000235:genetics*; D016174:Hepacivirus / Q000235:genetics*; D006526:Hepatitis C / Q000175:diagnosis; D006801:Humans; D008403:Mass Screening; D008969:Molecular Sequence Data; D010802:Phylogeny; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000097:blood*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000592:standards*; D012680:Sensitivity and Specificity; D017423:Sequence Analysis, RNA
D012367:RNA, Viral