Assessment of Rapid Diagnostic Tests Algorithms in Transfusion Medicine Setting

Background: The rapid diagnostic tests play a pivotal role in the screening of viral\r\nmarkers in blood qualification for transfusion in limited resource setting.\r\nTherefore, it is important to assess their analytical performances to ensure\r\ntheir proper functioning. Material and Methods: We performed\r\na cross- sectional study by successive recruitment to assess the diagnostic value\r\nof rapid diagnostic tests algorithms using ELISA as a reference test. A total\r\nof 661 blood from donors were enrolled for this study. Rapid Diagnostic Tests\r\n(RDTs) and ELISA tests were performed for each sample by a couple of\r\ndouble-blinded biotechnologists. Data were collected on case report form and\r\ncaptured in Microsoft Excel then the file was imported and analyzed using R\r\nsoftware version 4.0.3. Results: The diagnostic accuracy for the\r\nalgorithms are summarized in Table 1. For HIV-algorithm, the\r\ninternal validity parameters were as follow: sensitivity (sens) 99.0% (95% CI =\r\n97.8, 99.5); specificity (spec) 98.3% (95% CI = 90.9, 99.7); positive\r\nlikelihood ratio (PLR) 57.4 (95% CI = 8.2, 401.0); negative likelihood ratio\r\n(NLR) 0.01 (95% CI = 0.0005, 0.02); diagnostic odd ratio (DOR) 4710. HBV-Ag/Ab\r\nRDTs achieve the following diagnostic accuracy: sens 99.7% (95% CI = 98.3,\r\n99.9); spec 98.8% (95% CI = 96.9, 95.5); PLR 81.8 (95% CI = 30.9, 217.0); NLR\r\n0.003 (95% CI = 0.0004, 0.02); DOR 14,110. The\r\nanalytical performances of HCV-Ab RDTs were as follow: sens 98.7% (95% CI =\r\n97.5, 99.4); spec 93.1% (95% CI = 78.0, 98.1); PLR 14.3 (95% CI = 3.8, 54.5);\r\nNLR 1.5 (95% CI = 0.8, 2.8); DOR 962.6. The parameters evaluating the external\r\nvalidity of RDTs screening for the three viral markers when the theorical\r\nprevalence was 5% are summarized in Figure 3. At the prevalence , 99.99% and 99.94%. At the same prevalence, we found\r\nthe following Positive Predictive Values (PPV) 70.82%, 77.59% and 37.35% for\r\nHIV-Ag/Ab RDTs, HBV-Ag RDTs and HCV-Ab RDTs algorithms, respectively. The\r\noverall areas under the received operating characteristic (ROC) curves were\r\n98.6%, 99.2% and 99.2%; 95.9% for HIV-Ag/Ab RDTs, HBV-Ag RDTs and HCV-Ab RDTs\r\nalgorithms, respectively. Conclusion: RDTs algorithms can play a pivotal\r\nrole in the screening of HIV-Ab/Ag, HBs-Ag in the setting of resources\r\nlimited-countries where financial and technical expertise shortages are a\r\nstandard fare. However, their use for diagnostic purposes must be done with\r\ngreat caution and the result must necessarily be confirmed with an ELISA or\r\nmolecular technique particularly for HCV-RDTs algorithm which achieved an NLR\r\nvalue \u003e 0.1.