With this context, it is essential to assess the stability of DBS samples in different shipment temperatures and durations
With this context, it is essential to assess the stability of DBS samples in different shipment temperatures and durations. were bad on DBS. These 23 false negatives were tested a second time and the same results were obtained. A new cut-off value of 0.73 was collection for HCV results based on the level of sensitivity and specificity curves with respect to threshold ideals (Fig.?1). Five false negative results were managed after adjusting the S/Co value from 1 to 0.73. Therefore, a specificity of 98%, a level of sensitivity of 99%, a positive predictive value of 98% and a negative predictive value of 99% were acquired for anti-HCV detection using DBS. The Kappa index (0.97) shows an excellent agreement between the results obtained with plasma and DBS samples. Open in a separate window Fig.?1 Storyline of sensitivity and specificity versus signal-to-cutoff ideals of hepatitis C computer virus screening using DBS in Cameroon. Optimal cutoff value: 0.73 Discussion In this work, we evaluated the overall performance HBV and HCV testing using DBS. Similar to earlier study using the same method (Architect, Abbott diagnostics), for the detection of HBsAg, a perfect level of sensitivity (100%) and a good specificity (99%) were obtained with the DBS, and the kappa index (0.99) also indicated excellent agreement between plasma and DBS [6C8]. Although we applied a lower blood volume (50?L) on DBS than Ross et al. (100?L) and M?ssner et al. (75?L), used a lower elution answer (500?L vs 1000?L), and used a venous blood compared to the capillary blood used by M?ssner et al. Our results reinforce the good overall performance and confirm the robustness of the use of DBS in HBV screening [7, 8]. However, one should be cautious because Forbi et al. acquired a low level of sensitivity of 78.6% and a low specificity of 88.6% for detection of anti-HCV on DBS when using a lower blood volume (25?L) and a variable threshold value depending on the negative control in a study in Nigeria . This variability of the results according to the studies therefore justifies the overall performance evaluation of the DBS in the analysis of HBV or HCV for the NMS-P715 implementation of the useful recommendations. For the anti-HCV test, we acquired 23 false negatives and 100% specificity by applying the threshold value recommended by the manufacturer of Mouse monoclonal to SRA the kit (1). As reported previously , our data showed that all these 23 false negative samples experienced significantly lower mean titers than those acquired on plasma (DBS 0.5??0.2 vs plasma 3.4??1.9). Compared to earlier studies that experienced better sensitivities, the low level of sensitivity in the detection of HCV with this study could be explained by the low blood volume deposited on DBS [7, 8]. Additional authors possess indeed suggested that low blood quantities ( ?50 L) could significantly reduce the detection level of sensitivity of HCV [11, 12]. After modifying to the best cut-off value as proposed by other authors for the detection of anti-HCV on DBS [10, 12C14], we obtain 98% specificity and 99% level of sensitivity, which is consistent with earlier studies [7, 8]. Consequently our results suggest that a cut-off value of 0.73 NMS-P715 could be used for screening anti-HCV on DBS in our context. The low availability of specialized laboratories in remote areas is one of the major barriers to large scale screening for HBV and HCV in Africa. DBS could consequently become an alternative, simple and less expensive method to facilitate access to HBV and HCV testing especially for people living NMS-P715 in peripheral areas. In this context, it is essential to assess the stability of DBS samples in different shipment temps and durations..