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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., Materials and 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., Discussion: 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., (© 2024 The Author(s). Transfusion published by Wiley Periodicals LLC on behalf of AABB.)

Background: To investigate the transmission of SARS-CoV-2 via blood, we conducted retrospective molecular screening in blood donated during the first pandemic peak in the two French regions with the highest community transmission., Methods: Archived plasma samples randomly selected from donations collected between March 23 and 29, 2020, in Eastern and Northern regions of France were tested for SARS-CoV-2 RNA in minipools of 4 donations (MP4) using the Grifols ProcleixSARS-CoV-2 assay. Reactive MP4 and the four corresponding plasmas were further tested with alternative RT-PCRs and sequencing. Testing for SARS-CoV-2 antibodies and in vitro infectivity in cell culture were also performed., Results: Among the 2818 MP4 (corresponding to 9672 donations) tested for viral RNA, 5 were weakly reactive. Among the 20 plasmas included in these five MP4, one presented low-level reactivity with RT-PCRs and Procleix SARS-CoV-2 and was confirmed on sequencing. The estimated prevalence was 1.03/10,000 (95% CI 0-3.1). The 20 plasmas were antibody nonreactive and none of them showed cytopathic effects in cell culture. When recalled, the index-donor declared having had symptoms compatible with SARS-CoV-2 infection a few days after donation. The two immunocompromised recipients transfused with red blood cells and an inactivated pooled platelet product did not develop COVID-19., Conclusion: Our results indicated a low prevalence of SARS-CoV-2 RNA in the plasma of asymptomatic blood donors during the pandemic peak and no evidence of infectivity in vivo and in vitro. The transfusion risk remains theoretical and does not justify the implementation of SARS-CoV-2 NAT for blood donations., (© 2022 AABB.)

Background: The transfusion of platelet concentrates (PCs) contaminated with bacteria may cause serious, and even fatal, septic reactions in patients. The aim of this study was to compare the VersaTREK with the BACTEC FX automated culture systems for screening bacterial contamination, directly after the delay of 24 hours of preparation to obtain the final pooled buffy coat PCs, to prevent transfusion-transmitted bacterial infections., Study Design and Methods: Seven bacterial strains were each inoculated into five replicate pooled buffy coat PCs at approximately 100 colony-forming units/unit, and 5- or 10-mL samples were inoculated into duplicate aerobic culture bottles. The time and detection rates were compared between BACTEC FX, as a reference method, and VersaTREK., Results: Time to detection was significantly shorter using VersaTREK for most species detected by both systems for the volumes tested. Of 70 VersaTREK cultures, 69 (98.57% detection rate) were positive after 24 hours of incubation with the 5-mL sample. In contrast, the BACTEC FX system detected all positive samples in PCs for the volume of 10 mL, although seven samples were false negatives for the 5-mL volume., Conclusion: The VersaTREK system compared favorably to the BACTEC FX system for 5-mL volumes (p < 0.05) and could be considered a potential method for detecting bacterial contamination in PC samples directly after 24 hours of preparation of the final pooled buffy coat PCs., (© 2018 AABB.)

Background: Platelets (PLTs) are especially affected by the risk of bacterial contamination. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) is an accurate method for the routine identification of bacterial isolates in microbiology laboratories. We directly applied the MALDI-TOF method to bacterial detection in PLTs. In this study, we evaluated the sensitivity, specificity, and speed of a direct MALDI-TOF approach compared to the conventional method BACTEC., Study Design and Methods: Eight bacteria associated with PLT contamination, cited by the ISBT on transfusion-transmitted infectious diseases, were spiked into PLTs for a final concentration of approximately 100 CFU/bag (n = 5 for each strain). The PLTs were then agitated for 24 hours. One milliliter of PLTs was incubated in a shaker incubator for 8 hours at 37°C with 1 mL of trypticase soy broth (TSB). The spectra were analyzed using the MALDI Biotyper software. As a control, 8 mL of PLTs incubated into BACTEC bottles and a positive bottle were subcultured to ensure identification of bacterial growth., Results: Regardless of the strain of PLTs tested, MALDI-TOF analysis made detection and early identification possible at 8 hours. Analysis by BACTEC of PLTs infected with Escherichia coli, Bacillus cereus, and Providencia stuartii made early identification possible. For the remaining bacteria, the detection time by BACTEC was significantly longer than 8 hours., Conclusion: We demonstrated the possibility of detecting bacteria in PLTs using a standardized culture step in TSB with MALDI-TOF, regardless of the strain, with the same specificity and analytical sensitivity and with a time to results of 12 hours. This direct method presented rapid and reliable results., (© 2017 AABB.)

Background: Zika virus (ZIKV) has spread rapidly in the Pacific and throughout the Americas and is associated with severe congenital and adult neurologic outcomes. Nucleic acid amplification technology (NAT) assays were developed for diagnostic applications and for blood donor screening on high-throughput NAT systems. We distributed blinded panels to compare the analytical performance of blood screening relative to diagnostic NAT assays., Study Design and Methods: A 25-member, coded panel (11 half-log dilutions of a 2013 French Polynesia ZIKV isolate and 2015 Brazilian donor plasma implicated in transfusion transmission, and 3 negative controls) was sent to 11 laboratories that performed 17 assays with 2 to 12 replicates per panel member. Results were analyzed for the percentage reactivity at each dilution and by probit analysis to estimate the 50% and 95% limits of detection (LOD 50 and LOD 95 , respectively)., Results: Donor-screening NAT assays that process approximately 500 µL of plasma into amplification reactions were comparable in sensitivity (LOD 50 and LOD 95 , 2.5 and 15-18 copies/mL) and were approximately 10-fold to 100-fold more sensitive than research laboratory-developed and diagnostic reverse transcriptase-polymerase chain reaction tests that process from 10 to 30 µL of plasma per amplification. Increasing sample input volume assayed with the Centers for Disease Control and Prevention reverse transcriptase-polymerase chain reaction assays increased the LODs by 10-fold to 30-fold., Conclusions: Blood donor-screening ZIKV NAT assays demonstrate similar excellent sensitivities to assays currently used for screening for transfusion-transmitted viruses and are substantially more sensitive than most other laboratory-developed and diagnostic ZIKV reverse transcriptase-polymerase chain reaction assays. Enhancing sensitivities of laboratory-developed and diagnostic assays may be achievable by increasing sample input., (© 2017 AABB.)

Background: The operational and analytical performance of two automated triplex hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) nucleic acid test (NAT) systems were compared in four screening laboratories of the French Blood Service., Study Design and Methods: Two laboratories evaluated the Procleix Tigris system (Chiron/Gen-Probe) in individual donation (ID) format and two sites used the cobas s 201 system (Roche Molecular Systems) on minipools (MPs) of six donations. The analytical sensitivity, the specificity, and operational performance were compared., Results: The ID to MP-NAT relative sensitivity factors in standard dilution panels of different genotypes varied between 8.7 and 21.9 for HCV RNA, 6.7 and 14.8 for HIV RNA, and 0.71 and 11.6 for HBV DNA. Tigris was 800-fold more sensitive than cobas s 201 (1:6) for a HIV group O sample, but did not detect the HIV-2 sample picked up by cobas s 201 with equal sensitivity as the HIV-1 group M samples. The specificity of both NAT systems after initial screening of 10,520 donations with Tigris and 1444 test pools on s 201 was 99.9 percent for both systems, but reached 100 percent after the repeat and pool resolution test algorithms. A higher throughput of the pool test protocol on cobas s 201 became apparent when the daily workload was more than 400 donations., Conclusions: Tigris ID-NAT format was significantly more sensitive than cobas s 201 MP-NAT in detecting HCV RNA and HIV RNA dilution panels, but despite the 1:6 dilution factor in s 201 the difference in sensitivity was not significant for some of the HBV genotype panels. Both NAT systems demonstrated acceptable operational performance, but for routine use further improvement in system reliability is desirable.

Background: Accurate determination of the infectious window period (IWP) that remains with individual-donation (ID) or minipool (MP) NAT compared to those with serology assays is essential for residual risk estimations., Study Design and Methods: The relative sensitivity of the Procleix Tigris system (Gen-Probe/Chiron) used in ID-NAT format and cobas s 201 (Roche Molecular Systems) applied in 1:6 diluted samples to mimic six-minipool (MP6) nucleic acid test (NAT) was assessed by quadruplicate testing of five seroconversion panels per marker. A mathematical analysis based on the log-linear increase of viremia in the ramp-up phase, as established with bDNA 3.0 assays enabled estimation of the IWP for human immunodeficiency virus (HIV) and hepatitis B virus (HBV) assays., Results: The mean IWPs were Tigris HIV RNA 5.5 days, s 201 (1:6) HIV RNA 7.4 days, GenScreen Plus p24/anti-HIV 17.8 days, PRISM anti-HIV 19.0 days, Tigris HBV DNA 20.6 days, s 201 (1:6) HBV DNA 22.6 days, Bio-Rad hepatitis B surface antigen (HBsAg) 37.8 days, and PRISM HBsAg 35.5 days. At estimated 50 percent NAT seroconversion rates, s 201 (1:6) and Tigris showed mean window-period reduction times (WPRTs) of 30.5 to 35.5 days to hepatitis C virus antibody (anti-HCV) assays, 10.4 to 13.5 days to anti-HIV, or combination p24/anti-HIV assays and 12.8 to 17.2 days to HBsAg assays., Conclusions: Tigris ID-NAT detected HIV RNA 2 days earlier than s 201 MP6-NAT, but the difference in sensitivity between the two NAT systems was not significant in HBV seroconversion panels. Insufficient seroconversion samples were available for reliable modeling of WPRT in early HCV infection, but 1.4 to 2.0 days could be predicted by translating analytical sensitivity data. Both multiplex NAT systems demonstrate significant WPRTs compared to (combined) antigen and antibody assays.

Background: Until 1990, HCV infection was common in transfused patients, resulting in more than 200,000 cases of posttransfusion hepatitis C in France alone. A molecular method that permits the investigation of posttransfusion hepatitis C infections is presented., Study Design and Methods: Viral sequences in the envelope region of HCV were obtained for 12 pairs of blood recipients and their respective blood donors. The HCV strains studied belonged to types 1 (subtypes 1a and 1b), 2, 3, 4, and 5. Genetic distances and mutation rates were determined, and sequences were submitted to phylogenetic analysis along with sequences retrieved from nucleotide databases., Results: Pairwise distances in the donor-recipient pairs were found to be less than 0.05 mutation per site, which corresponds to a mutation rate ranging from 0.6 x 10(-3) to 2.1 x 10(-3) per site per year. Sequences obtained from the 12 donor-recipient pairs clustered in 12 monophyletic nests., Conclusion: The genetic analysis of the envelope region of HCV can be used for the forensic evaluation of virus transmission. It permits the refutation of a link between blood transfusion and HCV transmission, rather than proof of the existence of such a link.

Background: The purpose of this study was to determine the prevalence of TT virus (TTV) infection in voluntary blood donors in Southeastern France., Study Design and Methods: The sera of 289 blood donors were tested for the presence of TTV DNA by two PCR systems detecting genes located in the 5' UTR (primer set A [Set A]) and the open reading frame (ORF2) (primer set B [Set B]) of the viral genome. A randomized sample of 40 blood donors was also tested by a nested-PCR system in the ORF1 by use of primer set C (Set C). Donors were questioned for possible risk factors for virus transmission., Results: In the entire population studied, 30.8 percent of blood donors tested positive with both Sets A and B, and 70.6 percent with at least one set. In the sample tested with three sets of primers, 27.5 percent of blood donors were positive in testing with all PCR systems and 80 percent with at least one system. The specificity of TTV DNA amplification was confirmed by sequencing 10 PCR products obtained with each set of primers. Statistical analysis revealed that the prevalence of TTV reactivity increased with age., Conclusion: The high prevalence of TTV reactivity and the absence of a pathologic condition or risk factors obviously associated with the infection in blood donors suggest that there is no need for systematic detection of TTV infection before blood donation. Further studies are required to determine if TTV isolates can be responsible for a pathologic condition in humans after blood transfusion.

Background: The purpose of the study was to analyze serologic and molecular markers of the GB virus type C/hepatitis G virus (GBV-C/HGV) infection in voluntary blood donors from Southeastern France., Study Design and Methods: Sera were tested for the presence of GBV-C/HGV RNA by reverse transcriptase-polymerase chain reaction and that of antibodies to the GBV-C/HGV E2 (anti-E2) antigen by an enzyme-linked immunosorbent assay. A first cohort (1660 blood donors) was tested prospectively and a second cohort (238 samples with hepatitis markers) was tested retrospectively. Donors in the prospective study were questioned for possible risk factors of virus transmission. Amplification products were sequenced and subjected to phylogenetic analysis., Results: Approximately 2.6 percent of individuals accepted for blood donation and 15.4 percent with positive hepatitis C virus serologic tests carried GBV-C/HGV RNA. Anti-E2 was detected in these two populations in approximately 12 percent and 48 percent of donors, respectively. Moderate relative risks were found only in tattooed or pierced individuals (1.82) and health care workers (2.45). Almost all strains were located in the same phylogenetic branch as HGV Group 2., Conclusion: Though a large proportion of the donors tested have been in contact with GBV-C/HGV, no elevated relative risk of infection was identified. The phylogenetic distribution of viral strains suggests that the infection is endemic in this population.