BACKGROUND: The large dengue (DENV) and chikungunya (CHIKV) outbreaks observed during the last decade across the world, as well as local transmissions in non-endemic areas are a growing concern for blood safety. The aim of this study was to evaluate and compare the sensitivity of nucleic acid tests (NAT) detecting DENV and CHIKV RNA.
METHODS: Using DENV 1 to 4 International Standards, the limits of detection (LODs) calculated by probit analysis of two NAT assays; the cobas CHIKV/DENV assay (Roche Diagnostics) and the Procleix Dengue Virus Assay (Grifols) were compared. In addition, CHIKV-RNA LOD of the cobas CHIKV/DENV assay was evaluated.
RESULTS: For dengue, the 95% LOD of the cobas assay ranged between 4.10 [CI95%: 2.70-8.19] IU/mL (DENV-2) and 7.07 [CI95%: 4.34-14.89] IU/mL (DENV-4), and between 2.19 [CI95%: 1.53-3.83] IU/mL (DENV-3) and 5.84 [CI95%: 3.84-10.77] IU/mL (DENV-1) for Procleix assay. The Procleix assay had a significant lower LOD for DENV-3 (2.19 vs. 5.89 IU/mL) when compared to the cobas assay (p = 0.005). The 95% LOD for CHIKV-RNA detection of the cobas assay was 4.76 [CI95%: 3.08-8.94] IU/mL.
CONCLUSIONS: The two NAT assays developed for blood donor screening evaluated in this study demonstrated high and similar analytical performance. Subject to an appropriate risk-benefit assessment, they can be used to support blood safety during outbreaks in endemic areas or in non-endemic areas as an alternative to deferring blood donors during local transmission likely to affect the blood supply. The development of multiplex assays is expected to optimize laboratory organization.

BACKGROUND: Recently, high-sensitive troponin (hsTrop) assays consistent with professional societies\' recommendations became available. We aimed to summarize the evidence on the diagnostic accuracy of hsTrop on presentation.
METHODS: We searched electronic databases for studies evaluating the diagnostic accuracy of hsTrop in suspected acute coronary syndrome (ACS) patients. Random effect meta-analyses and meta-regression were performed. Primary and secondary analyses were restricted to studies using conventional Trop and hsTrop in the reference standard, respectively.
RESULTS: Fifteen studies with a total of 8,628 patients met the inclusion criteria for the primary analysis. hsTrop T (Hoffman-La Roche Ltd) and hsTrop I (Siemens) had sensitivities of 0.89 (95% confidence interval [CI]: 0.86-0.91) and 0.90 (95% CI: 0.87-0.92) and specificities of 0.79 (95% CI: 0.77-0.80) and 0.89 (95% CI: 0.87-0.90), respectively. There was no statistically significant difference in the area under the curve between hsTrop (95% CI: 0.920) and conventional Trop (95% CI: 0.929) at the 99th percentile (P=0.62). hsTrop at the level of detection had a sensitivity of 0.97 (95% CI: 0.96-0.98) and a specificity of 0.41 (95% CI: 0.40-0.42). The studies using a cut-off at coefficient of variance <10% as opposed to the 99th percentile for the conventional assay used for diagnosis reported higher diagnostic accuracy (relative diagnostic odds ratio =2.13, P=0.02). Five studies were included in the secondary analysis; hsTrop T (Hoffman-La Roche Ltd) had a sensitivity of 0.91 (95% CI: 0.89-0.93) and a specificity of 0.67 (95% CI: 0.63-0.70). There was significant heterogeneity among the studies.
CONCLUSIONS: hsTrop have excellent diagnostic accuracy for myocardial infarction on presentation, but may not outperform conventional Trop assays. The variation among the studies can be explained, in part, by the cut-off used for conventional Trop assays.