Evaluation of the Procleix TIGRIS System at the Blood Transfusion Service Berne Ltd. Dr. Martin Stolz BTS SRC Berne Ltd.
NAT testing in progress • HCV-PCR since 01 ‘1999 • HIV-1 PCR since 03‘ 2002 • increased blood safety • automized test procedures BTS SRC Berne Ltd.
Procleix TIGRIS System • fully automated NAT screening system • combined detection of 3 viruses: HIV-1, HCV and HBV • extraction/amplification/detection in one tube • extraction based upon magnetic bead technology • amplification based upon the TMA technology using RNA as amplified targed • detection by chemiluminescence • specific discrimination assays for virus identification BTS SRC Berne Ltd.
Design of the evalution study • Assay validation: • sensitivity, specificity, robustness & cross-contamination • Test performance under routine conditions • routine samples • pools of 8 or individual donations • pooling with Tecan pipetting robots • analysis with Procleix TIGRIS system BTS SRC Berne Ltd.
Sensitivity • HIV-1: 24.9 IU/ml(95 % C.I.: 20.2 – 33.3 IU/ml) ca. 13.9copies/ml • HCV: 3.7 IU/ml(95 % C.I.: 3.1 – 4.8 IU/ml)ca. 23.3 copies/ml • HBV: 7.6 IU/ml(95 % C.I.: 6.0 – 11.1 IU/ml)ca. 41.0copies/ml BTS SRC Berne Ltd.
Robustness and reproducibility • Procleix TIGRIS system: excellent robustness against cross-contamination • reproducibility: intra-, inter-assay precision and between laboratories confirmed • reliable test: 3 x 95% positive cut off value (HIV-1: 75 IU/ml, HCV: 11 IU/ml, HBV: 23 IU/ml) • high robustness against inhibiting substances i.e. 100 I.U. heparin per sample • no interference with lipaemic or haemolytic samples as a frequent donation related factor BTS SRC Berne Ltd.
Specificity – System Evaluation *) positive sample was a HBV window period donation BTS SRC Berne Ltd.
Summary • very good test sensitivity, robustness and reliability • clear discrimination between reactive and non reactive samples • low level of invalid samples • elevated level of „false“ positives with pools of 8 observed • pool resolving requires more time and large sample quantities • fully automated NAT screening system • test and software easy to handle • high throughput: single donation testing feasable • very high degree of automatisation, but demanding hardware and little flexibility BTS SRC Berne Ltd.
Acknowledgments • Christiane Schmidseder • Rita Hubschmid • Roger Hellmüller • Dr. Christoph Niederhauser • Dr. Philippe Schneider (BTS Lausanne) • Chiron Corp. BTS SRC Berne Ltd.
Window period HBV donation • identified by single donation testing • donation already transfused at time of testing • recipient developed a HBV viraemie 3 weeks post transfusion • viral load of the initial donation not available, but… • initial HBV titer must have been quite low: no longer detectable in a dilution of 1:8 and 1:24 • 101'621 IU/ml in 2nd donation 35 days later BTS SRC Berne Ltd.