Evaluation of GeneXpert and advanced biological laboratories UltraGene HCV diagnostic detection and performance against Roche real time PCR in Myanmar.

BACKGROUND: Developing countries experience limited access to HCV laboratory tests for different reasons. Providing near to real-time HCV testing and results especially to at-risk populations including those in rural settings for timely initiation to treatment is key. Within a rural Myanmar setting, we compared HCV diagnostic detection and quantification of the GeneXpert, and Advanced Biological Laboratories UltraGene-HCV assays against the gold standard and reference method Roche real-time HCV in Myanmar. METHODS: Blood samples from 158 high-risk individuals were assessed using three different methods at baseline. Results were checked for normality and log transformed. Log differences and bias between methods were calculated and correlated. Pearson's correlation coefficient was used to determine the association of HCV viral loads across all methods. The level of agreement with the standard method (Roche real time HCV) was assessed using Bland-Altman analyses. RESULTS: There was a strong positive correlation coefficient between all three methods with GeneXpert and Roche having the strongest, r = 0.96, (p<0.001). Compared to Roche, ABL (mean difference, 95 % limits of agreement; -0.063 and -1.4 to 1.3 Log10IU/mL) and GeneXpert (mean difference, 95 % limits of agreement; -0.28 and -0.7 to 1.8 Log10IU/mL) showed a good level of agreement with the GeneXpert being slightly superior. CONCLUSION: We demonstrate the excellent performance and no-inferiority, in terms of levels of agreements of both GeneXpert and ABL compared to the Roche platform and supporting the use of the POC assays as alternative a cost-effective methods in HCV detection and diagnosis in developing and low resource settings countries.

From Capillary Electrophoresis to Deep Sequencing: An Improved HIV-1 Drug Resistance Assessment Solution Using In Vitro Diagnostic (IVD) Assays and Software.

BACKGROUND: Drug-resistance mutations were mostly detected using capillary electrophoresis sequencing, which does not detect minor variants with a frequency below 20%. Next-Generation Sequencing (NGS) can now detect additional mutations which can be useful for HIV-1 drug resistance interpretation. The objective of this study was to evaluate the performances of CE-IVD assays for HIV-1 drug-resistance assessment both for target-specific and whole-genome sequencing, using standardized end-to-end solution platforms. METHODS: A total of 301 clinical samples were prepared, extracted, and amplified for the three HIV-1 genomic targets, Protease (PR), Reverse Transcriptase (RT), and Integrase (INT), using the CE-IVD DeepChek® Assays; and then 19 clinical samples, using the CE-IVD DeepChek® HIV Whole Genome Assay, were sequenced on the NGS iSeq100 and MiSeq (Illumina, San Diego, CA, USA). Sequences were compared to those obtained by capillary electrophoresis. Quality control for Molecular Diagnostics (QCMD) samples was added to validate the clinical accuracy of these in vitro diagnostics (IVDs). Nineteen clinical samples were then tested with the same sample collection, handling, and measurement procedure for evaluating the use of NGS for whole-genome HIV-1. Sequencing analyzer outputs were submitted to a downstream CE-IVD standalone software tailored for HIV-1 analysis and interpretation. RESULTS: The limits of range detection were 1000 to 106 cp/mL for the HIV-1 target-specific sequencing. The median coverage per sample for the three amplicons (PR/RT and INT) was 13,237 reads. High analytical reproducibility and repeatability were evidenced by a positive percent agreement of 100%. Duplicated samples in two distinct NGS runs were 100% homologous. NGS detected all the mutations found by capillary electrophoresis and identified additional resistance variants. A perfect accuracy score with the QCMD panel detection of drug-resistance mutations was obtained. CONCLUSIONS: This study is the first evaluation of the DeepChek® Assays for targets specific (PR/RT and INT) and whole genome. A cutoff of 3% allowed for a better characterization of the viral population by identifying additional resistance mutations and improving the HIV-1 drug-resistance interpretation. The use of whole-genome sequencing is an additional and complementary tool to detect mutations in newly infected untreated patients and heavily experienced patients, both with higher HIV-1 viral-load profiles, to offer new insight and treatment strategies, especially using the new HIV-1 capsid/maturation inhibitors and to assess the potential clinical impact of mutations in the HIV-1 genome outside of the usual HIV-1 targets (RT/PR and INT).

Alkaloids Extract from Linum usitatissimum Attenuates 12-OTetradecanoylphorbol- 13-Acetate (TPA)-induced Inflammation and Oxidative Stress in Mouse Skin.

BACKGROUND: In traditional medicine, Linum usitatissimum treats inflammatory, gastrointestinal, and cardiovascular diseases. OBJECTIVES: The present study aims to assess the anti-inflammatory and anti-oxidant effects of total alkaloid extract from Linum usitatissimum seeds (ALU) on the ear histological integrity and oxidant- antioxidant status in a mice model of a sub-chronic inflammation induced by multiapplication of TPA. METHODS: Topical TPA treatment induced various inflammatory changes, including edema formation, epidermal thickness, and the excess production of reactive oxygen species. Tissue samples were used for the measurement of reduced glutathione (GSH) and nitric oxide (NO) levels and Myeloperoxidase (MPO) and Catalase (CAT) activities. RESULTS: Oral administration of ALU (50, 100, and 200 mg/kg) produced anti-inflammatory and anti-oxidant effects. Also, ALU significantly reduced ear edema and inflammatory cell infiltration and restored the integrity of the ear. CONCLUSION: These findings suggest that the total alkaloid extract from Linum usitatissimum seeds presents significant anti-inflammatory and anti-oxidant effects on TPA-induced sub-chronic inflammation model in NMRI mice and can be used as an anti-inflammatory and anti-oxidant agent for the therapeutic management of inflammatory disorders.

Treatment outcomes and costs of a simplified antiretroviral treatment strategy for hepatitis C among Hepatitis C Virus and Human Immuno deficiency Virus co-infected patients in Ukraine.

Background and Aim: To demonstrate the use of a standard dose of ledipasvir (LDV) and sofosbuvir (SOF), with or without ribavirin, to treat hepatitis C and hepatitis C/HIV co-infection in Ukraine. Methods: Eligible HCV viraemic adults from two clinics in Kyiv were treated with LDV/SOF with or without weight-based ribavirin for 12 weeks. Clinical assessments were performed at screening and at week 24, and as needed; treatment was dispensed every 4 weeks. The primary outcome was sustained virologic response (SVR) 12 weeks after treatment, with analysis by intention to treat. Cost per patient was estimated in USD (2018) over the 24-week period. Results: Of 868 patients included in the study and initiated on therapy, 482 (55.5%) were co-infected with HIV. The common genotypes were 1 (74.1%) and 3 (22%). Overall, SVR was achieved in 831 of the 868 patients (95.7%). SVR in patients with hepatitis C alone and hepatitis C/HIV co-infection was 98.4% and 93.6%, respectively. Adverse events were infrequent and usually mild. Using generic medication, cost per patient was estimated at US$680. Conclusion: A standard dose of LDV and SOF, with ribavirin as per protocol, resulted in good outcomes for patients with both hepatitis C alone and co-infected with hepatitis C/HIV. Program costs in Ukraine were modest using generic medication.

A Distributed Multi-Hop Intra-Clustering Approach Based on Neighbors Two-Hop Connectivity for IoT Networks.

Under a dense and large IoT network, a star topology where each device is directly connected to the Internet gateway may cause serious waste of energy and congestion issues. Grouping network devices into clusters provides a suitable architecture to reduce the energy consumption and allows an effective management of communication channels. Although several clustering approaches were proposed in the literature, most of them use the single-hop intra-clustering model. In a large network, the number of clusters increases and the energy draining remains almost the same as in un-clustered architecture. To solve the problem, several approaches use the k-hop intra-clustering to generate a reduced number of large clusters. However, k-hop proposed schemes are, generally, centralized and only assume the node direct neighbors information which lack of robustness. In this regard, the present work proposes a distributed approach for the k-hop intra-clustering called Distributed Clustering based 2-Hop Connectivity (DC2HC). The algorithm uses the two-hop neighbors connectivity to elect the appropriate set of cluster heads and strengthen the clusters connectivity. The objective is to optimize the set of representative cluster heads to minimize the number of long range communication channels and expand the network lifetime. The paper provides the convergence proof of the proposed solution. Simulation results show that our proposed protocol outperforms similar approaches available in the literature by reducing the number of generated cluster heads and achieving longer network lifetime.

Treatment outcomes and costs of a simplified antiviral treatment strategy for hepatitis C among monoinfected and HIV and/or hepatitis B virus-co-infected patients in Myanmar.

Access to hepatitis C virus (HCV) testing and treatment is limited in Myanmar. We assessed an integrated HIV and viral hepatitis testing and HCV treatment strategy. Sofosbuvir/velpatasvir (SOF/VEL) ± weight-based ribavirin for 12 weeks was provided at three treatment sites in Myanmar and sustained virologic response (SVR) assessed at 12 weeks after treatment. Participants co-infected with HBV were treated concurrently with tenofovir. Cost estimates in 2018 USD were made at Yangon and Mandalay using standard micro-costing methods. 803 participants initiated SOF/VEL; 4.8% were lost to follow-up. SVR was achieved in 680/803 (84.6%) by intention-to-treat analysis. SVR amongst people who inject drugs (PWID) was 79.7% (381/497), but 92.5% among PWID on opioid substitution therapy (OST) (74/80), and 97.4% among non-PWID (298/306). Utilizing data from 492 participants, of whom 93% achieved SVR, the estimated average cost of treatment per patient initiated was $1030 (of which 54% were medication costs), with a production cost per successful outcome (SVR) of $1109 and real-world estimate of $1250. High SVR rates were achieved for non-PWID and PWID on OST. However, the estimated average cost of the intervention (under the assumption of no genotype testing and reduced real-world effectiveness) of $1250/patient is unaffordable for a national elimination strategy. Reductions in the cost of antivirals and linkage to social and behavioural health services including substance use disorder treatment to increase retention and adherence to treatment are critical to HCV elimination in this population.

Intracoronary or intravenous abciximab after aspiration thrombectomy in patients with STEMI undergoing primary percutaneous coronary intervention.

OBJECTIVE: To test whether aspiration thrombectomy with intracoronary (IC) instead of intravenous (IV) administration of abciximab could reduce the no-reflow phenomenon in patients undergoing primary percutaneous intervention (PCI) for ST-elevation myocardial infarction (STEMI). BACKGROUND: Despite recanalisation with PCI, failure to restore microvascular flow may affect the prognosis of patients with STEMI. A combination of aspiration thrombectomy with IC abciximab may improve distal perfusion. METHODS: After aspiration thrombectomy during primary PCI for STEMI, 160 patients were randomly assigned to either an IV or IC abciximab bolus delivered through the aspiration catheter, both followed by a 12-hour IV abciximab infusion. RESULTS: ST-segment resolution ≥ 70% was achieved in 36 of 78 patients with IC versus 30 of 82 patients with IV abciximab (46.1 vs 36.6%, p = 0.368), and partial resolution in 28 of 78 versus 31 of 82 patients (35.9 vs 37.8%, p = 0.368). Postprocedural myocardial blush grade (MBG) 3 was obtained in 62.8 vs 63.4% (p = 0.235) and MBG ≥ 2 in 89.7 vs 81.7% (p = 0.148) of patients given IC and IV abciximab, respectively. There were three deaths in each group (3.8%). Major adverse cardiac events occurred in six of 78 patients given the IC and seven of 82 patients given the IV abciximab bolus (7.6 vs 8.5%, p = 0.410). One stroke occurred in each group, and two patients in the IC and nine in the IV group developed renal failure (2.5 vs 10.9%, p = 0.414). CONCLUSIONS: IC versus IV abciximab did not enhance myocardial reperfusion in non-selected patients with STEMI undergoing primary PCI after aspiration thrombectomy had successfully been performed.

Baseline and post-treatment hepatitis C NS5A resistance in relapsed patients from a multicentric real-life cohort.

BACKGROUND: Recent data have suggested that failure to achieve sustained virological response with direct-acting antiviral therapy is usually due to relapse and is primarily associated with the emergence of resistance-associated substitutions. The aim of this study was to investigate the prevalence and characterization of non-structural-5A resistance-associated substitutions in patients infected with HCV genotypes 1, 3 and 4 treated by direct-acting antiviral therapy, including anti-non-structural-5A, and to characterize the pre-existing resistance-associated substitutions in subjects treated with anti-non-structural-5A inhibitors. METHODS: From January 2014 to March 2016, 2,995 patients infected with HCV genotypes 1, 3 and 4 were exposed to non-structural-5A inhibitors. Sequencing results at the time of virological failure were available for 61 patients; sequencing at baseline was available for 35 of these patients. RESULTS: Among the 35 patients with sequencing results available at baseline, 15 had no resistance-associated substitution, 16 had only one resistance-associated substitution, and 4 had more than one resistance-associated substitution. Resistance-associated substitutions were harbored in 57% of the sequences in the non-structural-5A region. Among the 61 patients sequenced at virological failure, 50 (82%) patients presented at least one resistance-associated substitutions inducing a high level of resistance to non-structural-5A inhibitors (>10-fold resistance). CONCLUSIONS: This pooled analysis suggests that non-structural-5A resistance-associated substitutions screening should be recommended when considering retreatment with a non-structural-5A inhibitor regimen in patients who have previously experienced failed non-structural-5A treatment.

Effects of eutrophication on the planktonic food web dynamics of marine coastal ecosystems: The case study of two tropical inlets.

We studied the plankton dynamics of two semi-enclosed marine coastal inlets of the north of Jurong Island separated by a causeway (SW Singapore; May 2012-April 2013). The west side of the causeway (west station) has residence times of ca. one year and is markedly eutrophic. The east side (east station) has residence times of one month and presents lower nutrient concentrations throughout the year. The higher nutrient concentrations at the west station did not translate into significantly higher concentrations of chlorophyll a, with the exception of some peaks at the end of the South West Monsoon. Microzooplankton were more abundant at the west station. The west station exhibited more variable abundances of copepods during the year than did the east station, which showed a more stable pattern and higher diversity. Despite the higher nutrient concentrations at the west station (never limiting phytoplankton growth), the instantaneous phytoplankton growth rates there were generally lower than at the east station. The phytoplankton communities at the west station were top-down controlled, largely by microzooplankton grazing, whereas those of the east station alternated between top-down and bottom-up control, with mesozooplankton being the major grazers. Overall, the trophic transfer efficiency from nutrients to mesozooplankton in the eutrophic west station was less efficient than in the east station, but this was mostly because a poor use of inorganic nutrients by phytoplankton rather than an inefficient trophic transfer of carbon. Some hypotheses explaining this result are discussed.

Non-proportional bioaccumulation of trace metals and metalloids in the planktonic food web of two Singapore coastal marine inlets with contrasting water residence times.

We analyzed the concentrations of trace metals/metalloids (TMs) in the water, sediment and plankton of two semi-enclosed marine coastal inlets located north of Jurong Island and separated by a causeway (SW Singapore; May 2012-April 2013). The west side of the causeway (west station) has residence times of approximately one year, and the east side of the causeway (east station) has residence times of one month. The concentrations of most of the TMs in water and sediment were higher in the west than in the east station. In the water column, most of the TMs were homogeneously distributed or had higher concentrations at the surface. Preliminary evidence suggests that the TMs are primarily derived from aerosol depositions from oil combustion and industry. Analyses of TMs in seston (>0.7µm; mostly phytoplankton) and zooplankton (>100µm) revealed that the seston from the west station had higher concentrations of most TMs; however, the concentrations of TMs in zooplankton were similar at the two stations. Despite the high levels of TMs in water, sediment and seston, the bioaccumulation detected in zooplankton was moderate, suggesting either the presence of effective detoxification mechanisms or/and the inefficient transfer of TMs from primary producers to higher trophic levels as a result of the complexity of marine planktonic food webs. In summary, the TM concentrations in water and seston are not reliable indicators of the bioaccumulation at higher trophic levels of the food web.

Clinical relevance of the HCV protease inhibitor-resistant mutant viral load assessed by ultra-deep pyrosequencing in treatment failure.

BACKGROUND: The detection of low frequency mutants in patients with hepatitis C virus (HCV) receiving direct-acting antivirals (DAAs) is still debated. The clinical relevance of the mutant viral load has not yet been evaluated. OBJECTIVES: To assess the viral load of resistance associated variants (RAVs) in patients at different time points, including the baseline, virological failure and one year after the cessation of therapy. STUDY DESIGN: The study included 22 patients who were previously treated with protease inhibitors (PI) (with telaprevir and boceprevir). For each patient, three time points were assessed using ultra-deep pyrosequencing (UDPS). RESULTS: Baseline mutations were observed in 14/22 patients (64%). At virological failure, RAVs were detected in 18/22 patients (82%). Persistent RAVs were observed in four HCV GT 1a patients (18%). Persistence mutations were found only in HCV GT 1a patients. The baseline relative V36M, R155K, R155T and A156T mutation load of patients with persistent RAVs was significantly higher (P<0.001) than those of patients without persistent RAVs. CONCLUSION: The UDPS follow-up analysis demonstrated that the presence of BOC or TLP-RAVs persist one year after therapy cessation only in HCV GT 1a patients. The relative mutant viral load should be considered prior to any PI based re-treatment. This concept of the baseline mutation viral load must be validated using current therapy and must be validated on a larger cohort.

[Direct and indirect ion selective electrodes methods: the differences specified through a case of Waldenström's macroglobulinemia]. / Potentiométries directe et indirecte : différences précisées à travers un cas de maladie de Waldenström.

Direct and indirect ion selective electrodes (ISEs) are two methods commonly used in biochemistry laboratories in order to measure the electrolytes such as sodium. In the clinical practice, it's the sodium concentration in plasma water -measured by direct ISE- which is important to consider as it is responsible of water movements between the liquid compartments. Knowing the difference between the two methods is important because there are situations leading to conflicting results between direct and indirect ISE, especially with sodium and inappropriate therapeutic decisions could be taken if the clinician is not aware of this difference. The increase and the decrease in plasma water volume are the situations that distort the results of the indirect ISE because this method, after a dilution step, does not take into account the real percentage of plasma water of the patient in the determination of the concentrations (leading for sodium to pseudohyponatremia, pseudonormonatremia or pseudohypernatremia). In the direct ISE, the sample is not diluted and the results are correct even if the volume of plasma water is modified. This article specifies the differences between the two techniques through a case of Waldenström's macroglobulinemia and proposes a course of action to follow for both of the biologist and the clinician.

Naturally Occurring Resistance-Associated Variants of Hepatitis C Virus Protease Inhibitors in Poor Responders to Pegylated Interferon-Ribavirin.

The pretherapeutic presence of protease inhibitor (PI) resistance-associated variants (RAVs) has not been shown to be predictive of triple-therapy outcomes in treatment-naive patients. However, they may influence the outcome in patients with less effective pegylated interferon (pegIFN)-ribavirin (RBV) backbones. Using hepatitis C virus (HCV) population sequence analysis, we retrospectively investigated the prevalence of baseline nonstructural 3 (NS3) RAVs in a multicenter cohort of poor IFN-RBV responders (i.e., prior null responders or patients with a viral load decrease of <1 log IU/ml during the pegIFN-RBV lead-in phase). The impact of the presence of these RAVs on the outcome of triple therapy was studied. Among 282 patients, the prevalances (95% confidence intervals) of baseline RAVs ranged from 5.7% (3.3% to 9.0%) to 22.0% (17.3% to 27.3%), depending to the algorithm used. Among mutations conferring a >3-fold shift in 50% inhibitory concentration (IC50) for telaprevir or boceprevir, T54S was the most frequently detected mutation (3.9%), followed by A156T, R155K (0.7%), V36M, and V55A (0.35%). Mutations were more frequently found in patients infected with genotype 1a (7.5 to 23.6%) than 1b (3.3 to 19.8%) (P = 0.03). No other sociodemographic or viroclinical characteristic was significantly associated with a higher prevalence of RAVs. No obvious effect of baseline RAVs on viral load was observed. In this cohort of poor responders to IFN-RBV, no link was found with a sustained virological response to triple therapy, regardless of the algorithm used for the detection of mutations. Based on a cross-study comparison, baseline RAVs are not more frequent in poor IFN-RBV responders than in treatment-naive patients and, even in these difficult-to-treat patients, this study demonstrates no impact on treatment outcome, arguing against resistance analysis prior to treatment.

Nationwide large survey on hepatitis B surface antigen quantification use in real-life clinical practice.

BACKGROUND AND AIM: Hepatitis B surface antigen quantification (qHBsAg) is a relevant biomarker assay in the therapeutic management of hepatitis B virus-infected patients; however, little is known about its use in France. The aim of this study was to describe the knowledge of qHBsAg use and the indications for the prescription of qHBsAg in France. METHODS: From March 2014 to May 2014, 135 questionnaires were sent to hepatologists and gastroenterologists from several health centers (private practice, public practice, and outlying health centers). There were 20 items in each questionnaire on the use of qHBsAg. RESULTS: Seventy-six percent of the practitioners had previously used qHBsAg, among whom 88% had prescribed the use of qHBsAg before treatment, 73% had prescribed the use of qHBsAg in combination with hepatitis B virus viral load, 64% had prescribed the use of qHBsAg at week 12 or week 24 of treatment, 62% had prescribed the use of qHBsAg for stopping rules, and 49% had prescribed the use of qHBsAg to identify inactive carriers. The reason for nonprescription of qHBsAg was mainly because of difficulty accessing the test (50% of the practitioners), followed by nonreimbursement of the test (27%); 97% of the practitioners who did not prescribe qHBsAg indicated an interest in accessing the test. CONCLUSION: This survey describes the characteristics of the prescription of qHBsAg in France. More than three out of four practitioners have previously used qHBsAg. The use of the qHBsAg just before treatment was the main reason for prescription. The main reason for nonprescription was because of difficulty in accessing the test.

Comparison of ultra-deep versus Sanger sequencing detection of minority mutations on the HIV-1 drug resistance interpretations after virological failure.

OBJECTIVE: Drug-resistance mutations are routinely detected using standard Sanger sequencing, which does not detect minor variants with a frequency below 20%. The impact of detecting minor variants generated by ultra-deep sequencing (UDS) on HIV drug-resistance interpretations has not yet been studied. DESIGN: Fifty HIV-1 patients who experienced virological failure were included in this retrospective study. METHODS: The HIV-1 UDS protocol allowed the detection and quantification of HIV-1 protease and reverse transcriptase variants related to genotypes A, B, C, F and G. DeepChek-HIV simplified drug-resistance interpretation software was used to compare Sanger sequencing and UDS. RESULTS: The total time required for the UDS protocol was found to be approximately three times longer than Sanger sequencing with equivalent reagent costs. UDS detected all of the mutations found by population sequencing and identified additional resistance variants in all patients. An analysis of drug resistance revealed a total of 643 and 224 clinically relevant mutations by UDS and Sanger sequencing, respectively. Three resistance mutations with more than 20% prevalence were detected solely by UDS: A98S (23%), E138A (21%) and V179I (25%). A significant difference in the drug-resistance interpretations for 19 antiretroviral drugs was observed between the UDS and Sanger sequencing methods. Y181C and T215Y were the most frequent mutations associated with interpretation differences. CONCLUSION: A combination of UDS and DeepChek software for the interpretation of drug resistance results would help clinicians provide suitable treatments. A cut-off of 1% allowed a better characterization of the viral population by identifying additional resistance mutations and improving the drug-resistance interpretation.

Clinical and analytical relevance of NNRTIs minority mutations on viral failure in HIV-1 infected patients.

The objective of this study was to assess the analytical and clinical relevance of minority variants using a new pyrosequencing (PSQ) assay and to detect minor variants with frequencies below the current 20% clinical setting limit. A PSQ approach for detecting and quantifying mutations was developed for the analysis of 14 codons of the human immunodeficiency virus (HIV) reverse transcriptase (RT) gene below the limit of conventional sequencing. Ten patients who experienced virological failure (VF) after a first-line regimen of lamivudine, tenofovir, and either efavirenz, nevirapine, or etravirine, as well as 10 controls patients without VF, were included in this retrospective study. Baseline plasma and plasma from the time of VF were assessed using Sanger sequencing and PSQ methods. The analytical sensitivity for the detection of minor sequence variants is 5%. At baseline, no minority variant was detected in 10/10 patient controls using both the Sanger sequencing and PSQ assays, whereas, two patients who failed therapy had baseline non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations that were not detected by the standard genotyping. At the time of VF, standard genotyping detected mutations in four out of the 10 VF patients, whereas, PSQ detected mutations in five out of the 10 VF patients. Clinically, minority mutations at a 10% level of detection can be assessed efficiently by pyrosequencing and used as a suitable predictor of the evolution of viral populations. These traits allow for a better interpretation of data analysis, which can help clinicians in providing a suitable treatment for HIV.

Dried blood spot sampling for hepatitis B virus serology and molecular testing.

BACKGROUND AIMS: Dried blood spots (DBS) on filter paper have been successfully used to diagnose and monitor several infectious diseases. The aim was to investigate the performance of DBS in hepatitis B virus (HBV) diagnosis using commercial tests in comparison to standard methods. METHODS: Paired DBS and plasma samples were collected from 200 patients: 100 patients with HBsAg negative status and 100 patients with HBsAg positive status. In the latter patient, HBeAg reactivity was tested. Ten samples of anti-HBs were collected from people vaccinated against HBV. We also studied 50 patients with positive HBV DNA viral load in plasma and 10 HBV DNA negative patients. HBV genotypes and gene polymerase mutations were determined in 10 randomly selected HBV-infected patients. The DBS sample consisted of 50 µL of whole blood, i.e. a 12-mm paper card. RESULTS: The sensitivity thresholds of HBsAg and anti-HBs antibody were 0.30 ± 0.08 IU/mL and 18.11 ± 6.05 IU/mL, respectively, for DBS with 98% sensitivity and 100% specificity. Sensitivity was 98% and specificity 100% for the detection of HBV DNA on a blotter, considering an HBV DNA threshold of 914.1 ± 157.8 IU/ml. Ten patients had an HBeAg positive status in plasma, all were detected positive using DBS. HBV genotyping and mutation detection were successfully performed on DBS, with full concordance between the 10 paired DBS and plasma samples. CONCLUSION: This study shows DBS is a reliable alternative to plasma specimens for quantifying and detecting HBsAg, anti-HBs, HBeAg and genotyping. DBS may increase the opportunities for HBV testing and treatment follow-up in hard-to-reach individuals.