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Evaluation of Rapid Screening Methods for Emergency Blood Collections. CPT Robert Gates, USA Armed Services Blood Program Update 12 February 2008. Agenda. Goal and Objectives Background Biokit evaluation Conclusion Other Tests-preliminary results (RV 236). Goal.
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Evaluation of Rapid Screening Methods for Emergency Blood Collections CPT Robert Gates, USA Armed Services Blood Program Update 12 February 2008
Agenda • Goal and Objectives • Background • Biokit evaluation • Conclusion • Other Tests-preliminary results (RV 236)
Goal Minimize TTD risk related to transfusion of freshly collected blood products in theatre
Objectives Rigorously evaluate the HCV and HBsAg rapid tests currently in use in theatre Assess all other candidate tests for future use
Background >250 freshly collected blood products are transfused into patients at US medical installations in OIF/OEF monthly Questionnaires and screening are either not performed or conducted in substandard fashion HIV, HCV, and HBV are rare but present in donors Rapid testing offers opportunity to mitigate risk
Biorapid Evaluation Aggregate data from: WWHV301 PHV106 PHW804 Sensitivity = .281 (.138-.468) Negative Likelihood Ratio (LR-) = .719 Specificity = 13/13 = 1.00 (.794-1.00)
Biorapid Evaluation Aggregate data from: PHA106 PHA206 PHA808 Sensitivity = .157 (.070-.286) Negative Likelihood Ratio (LR-) = .843 Specificity = 8/8 = 1.00 (.688-1.00)
HBV HCV
Biorapid Evaluation Sensitivity = .84 (.709-.928) Negative Likelihood Ratio (LR-) = .16 Specificity = 13/13 = 1.00 (.929-1.00) Aggregate data from: American Red Cross samples Roberson Donor Center samples
Biorapid Evaluation Sensitivity = .875 (.730-.889) Negative Likelihood Ratio (LR-) = .125 Specificity = 8/8 = 1.00 (.916-1.00) *18 Invalid tests Aggregate data from: American Red Cross samples Roberson Donor Center samples
Conclusions Biorapid Evaluation Biorapid preformed poorly against panel specimens, but had no invalid results Also poor against clinical samples (84% sensitivity for HCV, 87.5% sensitivity for HBsAg) and had an 18% invalid rate with the HBsAg test Conclusion: Biorapid hepatitis rapid tests should be replaced by tests that perform better
RV 236 • Seeks to identify best rapid assays for HCV and HBsAg • Tests selected based on published material, paring down from 30 HBsAg, and 29 HCV to 6 HCV and 4 HBsAg • Positive plasma down selection (N=50 per test) complete • Selected tests will be challenged in three stages: • -commercial panels (N = 54) • -clinical samples (N = 672) • -whole blood spiked with reactive plasma (N = 168) • Ease of Use Survey
* * * * * Sensitivity statistically superior Compared to Biorapid
DOWN SELECTION TEST DATA (HCV) *Sensitivity based on small sample group (n=50),** 7/50 invalids (14%)
PRELIMINARY DOWN SELECTION TEST DATA (HBsAg) *Sensitivity based on small sample group (n=50),** 1/50 invalid (2%),***3/50 invalid (6%),****18/100 invalid (18% based on n=100)