Hepatitis B virus testing by minipool nucleic acid testing: does it improve blood safety?

Estimating the prevalence of two or more diseases using outcomes from multiplex group testing

When screening a population for infectious diseases, pooling individual specimens (e.g., blood, swabs, urine, etc.) can provide enormous cost savings when compared to testing specimens individually. In the biostatistics literature, testing pools of specimens is commonly known as group testing or pooled testing. Although estimating a population-level prevalence with group testing data has received a large amount of attention, most of this work has focused on applications involving a single disease, such as human immunodeficiency virus. Modern methods of screening now involve testing pools and individuals for multiple diseases simultaneously through the use of multiplex assays. Hou et al. (2017, Biometrics, 73, 656-665) and Hou et al. (2020, Biostatistics, 21, 417-431) recently proposed group testing protocols for multiplex assays and derived relevant case identification characteristics, including the expected number of tests and those which quantify classification accuracy. In this article, we describe Bayesian methods to estimate population-level disease probabilities from implementing these protocols or any other multiplex group testing protocol which might be carried out in practice. Our estimation methods can be used with multiplex assays for two or more diseases while incorporating the possibility of test misclassification for each disease. We use chlamydia and gonorrhea testing data collected at the State Hygienic Laboratory at the University of Iowa to illustrate our work. We also provide an online R resource practitioners can use to implement the methods in this article.

Development and clinical validation of a one-step pentaplex real-time reverse transcription PCR assay for detection of hepatitis virus B, C, E, Treponema pallidum, and a human housekeeping gene

BACKGROUND

With the safety of blood transfusion being a major public health concern, the development of a rapid, sensitive, specific, and cost-effective multiplex PCR assay for simultaneous detection of hepatitis B virus(HBV), hepatitis C virus (HCV), hepatitis E virus (HEV), and Treponema pallidum(T. pallidum) in blood is crucial.

METHODS

Five primer pairs and probes were designed towards conserved regions of target genes and used to establish a one-step pentaplex real-time reverse transcription PCR(qRT-PCR) assay for simultaneous detection of HBV, HCV, HEV, T. pallidum, and RNase P(housekeeping gene), providing sample quality check. The clinical performance of the assay was further determined with 2400 blood samples from blood donors and patients in Zhejiang province, and compared the results with commercial singleplex qPCR and serological assays.

RESULTS

The 95% limit of detection(LOD) of HBV, HCV, HEV, and T. pallidum were 7.11 copies/µL, 7.65 copies/µL, 8.45 copies/µL, and 9.06 copies/µL, respectively. Moreover, the assay has good specificity and precision. Compared to the singleplex qPCR assay, the novel assay for detecting HBV, HCV, HEV, and T. pallidum presented 100% clinical sensitivity, specificity, and consistency. Several discrepant results between serological and pentaplex qRT-PCR assays were found. Of 2400 blood samples, there were 2(0.08%) HBsAg positive samples, 3(0.13%) anti-HCV positive samples, 29(1.21%) IgM anti-HEV positive samples and 6(0.25%) anti-T. pallidum positive samples proven negative in nucleic acid detection. 1(0.04%) HBV DNA positive sample and 1(0.04%) HEV RNA positive sample were detected negative by serological testing.

CONCLUSIONS

The developed pentaplex qRT-PCR is the first assay on simultaneous, sensitive, specific, and reproducible detection of HBV, HCV, HEV, T. pallidum, and RNase P in a single tube. It could detect pathogens in blood during the window period of infection and is a good tool for effectively screening blood donors and early clinical diagnosis.

Comparison of Two Different Serological Viral Marker Testing Assays for Screening of Apheresis Donors: Which Assay Provides Optimum Safety for Transfusion?

While whole blood testing has evolved over the years, viral marker testing for plateletpheresis donors is still performed by Rapid Diagnostic Tests (RDT). Aim of this study was to compare diagnostic accuracy of RDT and Chemiluminescence Immunoassay (CLIA) in serological testing for HBsAg, anti-HCV and anti-HIV antibodies. A prospective, analytical study was conducted in the department of Transfusion Medicine at a tertiary healthcare center in India between September 2016 and August 2018. Samples were simultaneously tested by CLIA, RDT and a confirmatory test. Sensitivity, specificity, negative and positive predictive values and mean time taken to report results were calculated. A total of 102 (1.48%) of the 6883 samples were found to be reactive by either or both the assays. A total of 74 (1.08%) samples were HBsAg reactive, 23 (0.33%) were reactive for anti-HCV antibodies and 5 (0.07%) were reactive for anti-HIV I and II antibodies. A combined sero-prevalence of 1.05% (72) was observed; 0.78% (54) for HBsAg, 0.26% (18) for anti-HCV antibodies and none for anti-HIV I and II antibodies. Four (3.85%) reactive samples were missed by RDT and therefore sensitivity of RDT was quite less as compared to CLIA. RDT and CLIA both were found to have a statistically significant shorter turnaround time than confirmatory tests. There is increasing need to develop a safe donor screening strategy for plateletpheresis. CLIA offers an excellent alterative to RDT for viral marker testing in terms of sensitivity.

Evaluation of Six Years of Appropriateness Level of Blood Transfusion in a Pediatric Ward

BACKGROUND

Blood transfusion can be considered as a life-saving treatment and is a primary health management topic. This study aims to assess the appropriateness of blood transfusion performed in a large tertiary hospital in Italy.

METHODS

a multispecialist team composed oof hematologists, public health experts and pediatricians analyzed blood transfusions performed between 2018 and 2022 in the pediatric wards comparing the appropriateness with the available NHS guidelines available. Patients' characteristics, clinical features and blood component's data were collected and analyzed.

RESULTS

considering 147 blood transfusions performed in 2018-2022, only eight (5.4%) were performed according to guidelines, while 98 (66.7%) were driven by clinicians' expertise, especially for anemia in genetic syndromes (30) (20.5%) and autoimmune diseases (20) (13.6%). Thirty-nine (26.5%) transfusions could be considered as inappropriate, while two (1.4%) blood packs were never been transfused after being requested.

CONCLUSIONS

This analysis is one of the first performed to assess the appropriateness of blood component transfusions comparing their compliance to NHS guidelines. The importance of this analysis can be explained first by the clinical point of view and second by the economic one.

Over-transfusion with blood for suspected hemorrhagic shock is not associated with worse clinical outcomes

BACKGROUND

We evaluated patient outcomes after early, small volume red blood cell (RBC) transfusion in the setting of presumed hemorrhagic shock. We hypothesized that transfusion with even small amounts of blood would be associated with more complications.

STUDY DESIGN AND METHODS

Retrospective review of trauma patients admitted to a Level 1 trauma center between 2016-2021. Patients predicted to require massive transfusion who survived ≥72 h were categorized according to units of RBCs transfused in the first 24 h. A Cox regression model stratified by dichotomized ISS and adjusted for SBP <90 mm Hg and pulse >120 bpm on arrival was used to estimate hazard ratios (HRs) for outcomes of interest.

RESULTS

A total of 3121 (24%) received RBC transfusion within the first 24 h. Massive transfusion protocol (MTP) was activated in 38% (1188/3121): 17% received no RBCs, 27.4% 1-3 units, 32.4% 4-9 units, and 22.7% ≥10 units. Mean ISS increased with each category of RBC transfusion. There was no difference in the risk of acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), infection, cardiac arrest, venous thromboembolism or stroke for patients receiving 1-3 units compared to the non-transfused group or 4-9 units group (p > 0.05). Compared to those receiving ≥10 units, the 1-3 units group had a significantly lower risk of AKI, ARDS, and cardiac arrest.

DISCUSSION

Early empiric RBC transfusion for presumed hemorrhagic shock may subject patients to potential over-transfusion and end-organ damage. Among patients meeting clinical triggers for MTP, 1-3 units of allogeneic RBCs is not associated with worse outcomes.

The Mirasol Evaluation of Reduction in Infections Trial (MERIT): study protocol for a randomized controlled clinical trial

BACKGROUND

Transfusion-transmitted infections (TTIs) are a global health challenge. One new approach to reduce TTIs is the use of pathogen reduction technology (PRT). In vitro, Mirasol PRT reduces the infectious load in whole blood (WB) by at least 99%. However, there are limited in vivo data on the safety and efficacy of Mirasol PRT. The objective of the Mirasol Evaluation of Reduction in Infections Trial (MERIT) is to investigate whether Mirasol PRT of WB can prevent seven targeted TTIs (malaria, bacteria, human immunodeficiency virus, hepatitis B virus, hepatitis C virus, hepatitis E virus, and human herpesvirus 8).

METHODS

MERIT is a randomized, double-blinded, controlled clinical trial. Recruitment started in November 2019 and is expected to end in 2024. Consenting participants who require transfusion as medically indicated at three hospitals in Kampala, Uganda, will be randomized to receive either Mirasol-treated WB (n = 1000) or standard WB (n = 1000). TTI testing will be performed on donor units and recipients (pre-transfusion and day 2, day 7, week 4, and week 10 after transfusion). The primary endpoint is the cumulative incidence of one or more targeted TTIs from the Mirasol-treated WB vs. standard WB in a previously negative recipient for the specific TTI that is also detected in the donor unit. Log-binomial regression models will be used to estimate the relative risk reduction of a TTI by 10 weeks associated with Mirasol PRT. The clinical effectiveness of Mirasol WB compared to standard WB products in recipients will also be evaluated.

DISCUSSION

Screening infrastructure for TTIs in low-resource settings has gaps, even for major TTIs. PRT presents a fast, potentially cost-effective, and easy-to-use technology to improve blood safety. MERIT is the largest clinical trial designed to evaluate the use of Mirasol PRT for WB. In addition, this trial will provide data on TTIs in Uganda.

TRIAL REGISTRATION

Mirasol Evaluation of Reduction in Infections Trial (MERIT) NCT03737669 . Registered on 9 November 2018.

Assessing the global burden of hemorrhage: The global blood supply, deficits, and potential solutions

There is a critical shortage of blood available for transfusion in many low- and middle-income countries. The consequences of this scarcity are dire, resulting in uncounted morbidity and mortality from trauma, obstetric hemorrhage, and pediatric anemias, among numerous other conditions. The process of collecting blood from a donor to administering it to a patient involves many facets from donor availability to blood processing to blood delivery. Each step faces particular challenges in low- and middle-income countries. Optimizing existing strategies and introducing new approaches will be imperative to ensure a safe and sufficient blood supply worldwide.

Blood Product (Donor) Noninfectious and Infectious Testing and Modification

Blood transfusion begins with safe donor selection and testing. In the United States, the blood supply and transfusion are highly regulated. Blood transfusion safety is multifaceted, whereby each of the elements of the blood safety value chain, spanning donor recruitment and qualification, to collection, blood processing, testing, transfusion practice, and posttransfusion surveillance, must be optimized to minimize risk. Pathogen inactivation is a promising approach to decrease bacterial contamination of platelets, inactivate parasites and viruses, and decrease risks associated with emerging and unidentified pathogens. This article offers an overview of blood donor infectious and noninfectious testing in the United States.

Residual risk of transfusion-transmitted hepatitis B virus (TT-HBV) infection by NAT-screened blood components: A review of observed versus modeled infectivity from donors with window period and occult HBV infections

BACKGROUND

The residual transfusion-transmitted hepatitis B virus (TT-HBV) risk with different testing strategies depends on the sensitivity of screening assays, the prevalence of hepatitis B surface antigen (HBsAg) compared to HBV-DNA in window period (WP) and occult HBV infections (OBIs), and infectivity of blood in these infection stages. We compared modeled WP and OBI transmission risk in a multiregional individual donation nucleic acid amplification technology (ID-NAT) screening study with observed TT-HBV infection rates in several lookback studies.

STUDY DESIGN AND METHODS

The WP and OBI risk was estimated from ID-NAT screening data in six geographic regions. The 50% infectious dose (ID₅₀ ), a key factor in the applied risk models, was assumed to be 100-fold higher in OBI than in WP blood. The relative proportion of WP and OBI TT-risk was estimated for different screening scenarios and expressed as a percentage of the ID-NAT yield rate to allow for comparison with observed TT-rates in lookback studies.

RESULTS

Despite sevenfold to eightfold higher HBV ID-NAT yield rates in OBI than WP in South-East Asia and Europe, our models predicted that 40 (26-55)% of total residual TT-HBV risk was due to OBI, comparable to 37% observed in a Japanese hemovigilance study. Modeled TT-OBI risk was approximately 10-fold higher than observed rates of 2%-8% in five lookback studies but comparable to one other study (36%).

CONCLUSION

Although the observed TT-OBI rate was generally lower than the modeled risk, the relative risk of WP versus OBI transmission was not incompatible with the observational infectivity data. This supports the validity of our assumptions in the infectivity-based models for estimating worst-case residual risk with different testing scenarios.

Directed Donation: Special Considerations and Review for Contemporary Clinical Practices

Background: Directed blood donation is defined as the donation of blood or its components for the purpose of transfusion into a specified individual. Directed blood donation holds historic significance, and although practices as of 2021 encourage voluntary, nonrenumerated blood donations, public interest in directed donation remains. Requests to discuss the risks and benefits of directed donations are a common inquiry for transfusion medicine, transplant, and hematology/oncology professionals. This narrative review discusses the history of directed donation and summarizes directed donation considerations in the context of modern transfusion practices. Methods: We conducted a systematic search of PubMed for published literature on the topic of directed blood donation and gathered information about its benefits and potential harms with respect to the variety of products used in transfusion medicine. Results: The drawbacks of directed donation include transfusion-transmitted infection risk, alloimmunization risk, increased transfusion-associated graft vs host disease risk, decreased expediency in treatment, and increased administrative burdens. However, a role remains for directed blood donation in specific patient populations, such as individuals with rare blood types or immunoglobulin A deficiencies, because of the difficulties in finding compatible blood for transfusion. Conclusion: Clinicians should consider the risks and benefits when discussing directed blood donations with patients and family members.

Hepatitis B infections among blood donors in England between 2009 and 2018: Is an occult hepatitis B infection a risk for blood safety?

INTRODUCTION

Hepatitis B virus (HBV) is one of the most frequent infections identified in blood donors in England and represents an ongoing blood safety risk. We have analyzed markers of HBV infections in blood donors in England between 2009 and 2018 and used these to estimate the likelihood of non-detection of occult HBV infection (OBI).

METHODS

We collected epidemiological, virological, and genotyping information on HBV cases identified in England, 2009-2018. The estimated risk of non-detection and likely transmission of OBI were compared to lookback and transfusion-transmitted infections surveillance data.

RESULTS

Six-hundered and fifty-five HBV-infected blood donors were identified in England during the 10-year period; 598 chronic, 32 acute, and 25 occult HBV infections. However, most donors with chronic and occult infections were born in Eastern Europe, Africa, or Asia (451/544, 83% and 14/24, 58%); acute infections were largely seen in UK-born donors (19/28, 68%). Genotyping of 266 HBV-positive samples revealed five genotypes (A-E), reflecting ethnicity and country of birth. Most OBIs were identified in repeat donors (19/25); lookback data identified a transmission rate of 8.3%. It is estimated that at least 13 potentially infectious donations from donors with OBI remain undetected annually, equating to an overall residual transmission risk of 3.1 per million donations using our current screening strategy of HBsAg screening with HBV nucleic acid testing (NAT) in pools of 24.

CONCLUSIONS

OBI accounted for the majority of the HBV residual risk in England. Further cost-benefit analysis is required to estimate if our current HBV screening strategy should be changed.

Hepatitis B virus prevalence in first-time blood donors in Flanders, Belgium: Impact of universal vaccination and migration

BACKGROUND

Transfusion-transmissible infections such as hepatitis B virus (HBV) remain a major concern for the safety of blood transfusion. This cross-sectional study aimed to assess the trend of HBV prevalence and associated risk factors among a first-time donor population in a low endemic country.

STUDY DESIGN AND METHODS

Between 2010 and 2018, blood samples were collected from first-time donors presented at donor collection sites of Belgian Red Cross-Flanders. They were tested for hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc), and HBV DNA, HIV and hepatitis virus C (HCV) antibodies and RNA, and syphilis antibodies.

RESULTS

A total of 211,331 first-time blood donors (43.7% males, median age 25 years) were analyzed. HBsAg prevalence decreased from 0.06% in 2010 to 0.05% in 2018 (p = .004) and this declining trend was accompanied by an increased number of donors in the HBV vaccinated birth cohort (p < .001). HBsAg prevalence was 0.33% in foreign-born donors and 0.02% in Belgian natives (p < .001). Multivariate risk profiling showed that anti-HBc positivity was significantly associated with mainly foreign-born donors (odds ratio [OR] = 9.24) but also with older age (OR = 1.06), male gender (OR = 1.32), year of blood donation (OR = 0.94), and co-infections with HCV (OR = 4.31) or syphilis (OR = 4.91).

DISCUSSION

The decreasing trend in HBV prevalence could mainly be explained by the introduction of the universal HBV vaccination. Being born in endemic areas was the most important predictor for HBV infection while the co-infections with syphilis suggest unreported sexual risk contacts.

HIV, HCV, and HBV incidence and residual risk in US blood donors before and after implementation of the 12-month deferral policy for men who have sex with men

BACKGROUND

In December 2015, the men who have sex with men (MSM) deferral was reduced to 12 months in the United States. We compared human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) incidence and residual risk before and after this policy change using data from >50% of the US blood supply.

STUDY DESIGN AND METHODS

Three estimation intervals from the Transfusion-Transmissible Infections Monitoring System were compared: 15-months pre- and two consecutive, nonoverlapping 15-month post-MSM deferral implementation. Repeat, first-time, and weighted all-donor incidences were estimated. Residual risk was calculated for all incidence estimates using the incidence/window-period method.

RESULTS

HIV repeat donor incidence was 1.57 per 100 000 person-years (phtpy) in the second 15-month post change and not significantly different from pre-MSM incidence of 2.19 phtpy. Similar values were seen for HCV (1.49 phtpy vs 1.46 phtpy) and HBV (1.14 phtpy vs 0.97 phtpy). In some cases, higher estimated incidence, but without significant change from pre-MSM to the second post change period occurred for males and first-time donors (eg, first-time donors, second post change period: 6.12 phtpy HIV, 6.41 phtpy HCV and 5.34 phtpy HBV). Estimated per donation residual risk was 1:1.6 million for HIV, 1:2.0 million for HCV and 1:1.0 million for HBV based on weighted incidence for all donors.

CONCLUSIONS

Repeat, first-time, and overall donor incidence did not vary significantly comparing pre-MSM to either of the post-MSM estimation intervals. Residual risk estimates vary by study, but all yield residual risks in the United States of ≤1 per million, and thus far have not shown increasing risk with the 12-month MSM policy change.

Frequency of Hepatitis B, C and HIV Infections among Transfusion-Dependent Beta Thalassemia Patients in Dhaka

Transfusion transmitted infections have remained a major deterrent to public health, particularly among the patients with transfusion-dependent Beta thalassemia in developing countries. Although proper donor selection through adoption of WHO-advised infection panel has lowered the rate of infections, the multi-transfused patients are not free of risk. In this study, we screened 148 transfusion-dependent Beta thalassemia patients to determine the frequency of Hepatitis C Virus (HCV), Hepatitis B Virus (HBV) and Human Immunodeficiency Virus (HIV) using the ELISA method. Among them, infected cases with HCV, HBV and HIV were 13.51%, 3.37% and 0%, respectively. Moreover, 2% of the patients were found to be co-infected with both HBV and HCV. The percentage of infections in the patients with frequent transfusion interval (≤30 days) was significantly higher (p < 0.0005) than that in the patients with less frequent transfusion intervals (>30 days). Immunochromatography (ICT)-based rapid test kits are usually used to screen and confirm these infections in the blood of the patients. However, ICT-based tests are not sensitive enough to detect the infections. So, a combination of both Nucleic Acid testing (NAT) and serological testing are suggested to significantly reduce the risk of viral infections during blood transfusion.

Considerations for Group Testing: A Practical Approach for the Clinical Laboratory

Group testing, also known as pooled sample testing, was first proposed by Robert Dorfman in 1943. While sample pooling has been widely practiced in blood-banking, it is traditionally seen as anathema for clinical laboratories. However, the ongoing COVID-19 pandemic has re-ignited interest for group testing among clinical laboratories to mitigate supply shortages. We propose five criteria to assess the suitability of an analyte for pooled sample testing in general and outline a practical approach that a clinical laboratory may use to implement pooled testing for SARS-CoV-2 PCR testing. The five criteria we propose are: (1) the analyte concentrations in the diseased persons should be at least one order of magnitude (10 times) higher than in healthy persons; (2) sample dilution should not overly reduce clinical sensitivity; (3) the current prevalence must be sufficiently low for the number of samples pooled for the specific protocol; (4) there is no requirement for a fast turnaround time; and (5) there is an imperative need for resource rationing to maximise public health outcomes. The five key steps we suggest for a successful implementation are: (1) determination of when pooling takes place (pre-pre analytical, pre-analytical, analytical); (2) validation of the pooling protocol; (3) ensuring an adequate infrastructure and archival system; (4) configuration of the laboratory information system; and (5) staff training. While pool testing is not a panacea to overcome reagent shortage, it may allow broader access to testing but at the cost of reduction in sensitivity and increased turnaround time.

Screening Blood Donors for HIV, HCV, and HBV at the American Red Cross: 10-Year Trends in Prevalence, Incidence, and Residual Risk, 2007 to 2016

Prevalence, incidence and residual risk of HIV, HCV and HBV are critical indicators of the safety of the blood supply. The American Red Cross routinely monitors these markers. Herein the results of testing over 58 million donations from 2007 to 2016 are reported. The prevalence and incidence of these infections has declined or remained essentially stable over the 7.5 to 10-year period. In 2015 to 2016, the prevalence of HIV, HCV and HBV were respectively: 1.65, 11.47 and 5.85 per hundred thousand (pht) donations with a significant decrease over the 10-year study only for HCV. Weighted incidence rates for all positives were 1.98 pht person years (py) for HIV, 2.20 pht py for HCV and 1.25 pht py for HBV. Estimates of residual risk using these incidence rates were: HIV, 1:2.3 million; HCV, 1:2.6 million; and HBV, 1:1.5 million donations, reflecting very low risk to recipients. There have been increases in the safety of the blood supply compared to prior published estimates. Demographic factors were shown to be associated with variations in infection prevalence and incidence. Continuing changes in the structure of the donor population or changes in policy could impact these measures of safety.

Detection of hepatitis B virus infection in German blood donors 2008-2015

BACKGROUND AND OBJECTIVES

Assessment of HBV-NAT testing compared to HBsAg and anti-HBc screening in German blood establishments for the period 2008-2015.

MATERIALS AND METHODS

Blood donations screened for HBsAg and anti-HBc along with HBV-NAT were evaluated. Sensitivity of HBsAg and HBV-NAT tests was compared in 30 HBV seroconversion panels and with the viral load of the NAT-only cases. Residual risk for HBV in the WP was modelled.

RESULTS

A total of 45 270 111 donations were evaluated. There were 29 NAT-only cases in the HBsAg-negative HBV-WP, one by ID-NAT and 28 by MP-NAT. MP-NAT, on average, showed higher sensitivity than HBsAg testing: MP-NAT-LoD of 146 IU/ml vs. 362 IU/ml HBV DNA for positive HBsAg detection (range 135-1502 IU/ml), resulting in 3·1 days (range 2·0-4·8 days) earlier HBV detection. Viral loads of the NAT-only cases confirmed the sensitivity of the HBV tests in the seroconversion study. One HBsAg-negative case was due to a new HBsAg mutant combination. There was one HBsAg-reactive only case. In addition, HBV incidence in the HBV-WP included 41 HBsAg-/HBV-NAT-positives and three HBV transmission cases. The residual risk for HBsAg was estimated to be 1:1 619 419-1 268 474 compared to 1:2 793 365-2 134 702 for MP-NAT. Within chronic HBV (HBsAg-/anti-HBc-positive and MP-NAT-negative) 70% were ID-NAT positive at low viral load (median 20 IU/ml). Among anti-HBc-only, supplementary ID-NAT detected 23 occult HBV infections.

CONCLUSIONS

In the HBV-WP, MP-NAT provided a higher sensitivity than HBsAg testing, obtained a considerably higher yield and reduced the risk for HBV transmission. In later HBV stages, anti-HBc screening and HBV-ID-NAT intercepted potentially infectious donations.

Direct comparison of three residual risk models for hepatitis B virus window period infections using updated input parameters

BACKGROUND AND OBJECTIVES

Comparison of two models for estimating residual transfusion transmission risk by NAT screened window period (WP) donations in South African repeat donors gave identical results for HIV but not for HBV. In order to understand discrepant HBV modelling outcomes, the values of input parameters in three HBV WP risk models were reviewed and subsequently applied to the same South African screening data generated by HBsAg PRISM and two NAT assays (Ultrio and Ultrio Plus). Two of the models were also compared using individual donation (ID)-NAT screening data from different geographical regions.

METHODS

Values of input parameters were derived from two published data sources and used in three risk models [(1) the incidence rate-WP risk day equivalent model, (2) the NAT yield WP ratio model and (3) the anti-HBc-negative HBsAg yield period ratio model] and subsequently applied to the same ID-NAT screening data.

RESULTS

The HBV WP transmission risk in South African repeat donations during a one-year Ultrio Plus NAT screening period was estimated as 22, 43 and 17 per million, respectively, for the three models, as compared to 56, 117 and 48 per million for HBsAg PRISM screening. The approximate two-fold higher estimate calculated with the NAT yield WP ratio model was corroborated in repeat donations from three of four regions in a multi-regional study. When another set of model input values (with shorter viraemia periods and a higher proportion of acute occult infections) was applied to the South African screening data, the relative difference in risk estimates between the three models became smaller.

CONCLUSIONS

Window period risk modelling for HBV is more complex than for HIV. Multiple factors affect the modelling outcomes. These include the values used for the length of transient HBsAg and HBV-DNA-positive phases, the proportion of acute occult and vaccine breakthrough infections and the assumption of random appearance of donors throughout the entire acute resolving infection phase. A substantial proportion of HBV WP NAT yields have very low viral load and lack donor follow-up data calling into question their definitive classification into the early acute (infectious) replication stage. Since these possible WP NAT yields most highly impact the NAT yield WP ratio model, we recommend relying on the more conservative estimates of the incidence rate-WP risk day equivalent model.

Evolution of the residual risk of HBV, HCV and HIV transmission through blood transfusion in the Region of Valencia, Spain, during a 15-year period (2003-2017)

BACKGROUND

Towards the end of the 20th century, transfusion-transmitted viral infections (TTVI) represented a huge problem for public health. From the beginning of the screening of blood donations, this risk has decreased to the point that it is no longer possible to measure it directly and it is necessary to use mathematical models. Using one of these models, the aim of this study was to analyse the evolution of the residual risk of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) transmission through blood transfusion from 2003 to 2017 in the Region of Valencia, Spain.

MATERIALS AND METHODS

Using data from the Blood Transfusion Centre of the Valencian Community, the incidence rate in donors and the residual risk were calculated for each agent and year by applying the most updated version of the incidence/window period model. For the set of the three viruses, these magnitudes were calculated as the algebraic sum of the specifics ones for each of them. The evolution of both magnitudes was analysed by the Mann-Kendall trend test and the Sen estimation of trend slope.

RESULTS

The residual risks obtained vary depending on the agent and the year. Considering the three viruses jointly, they range from 1 per 360,380 to 1 per 44,715 donations. During the study period, there was a statistically significant downward trend in the incidence rate of HBV (p<0.05, trend slope -0.88), the residual risk of HBV (p<0.0005, slope -0.98), and the joint residual risk for the three viruses (p<0.0001, slope -0.99).

DISCUSSION

The current risk of TTVI is very low in the Region of Valencia. In the last 15 years, there has been a reduction in the donor incidence rate and in the residual risk for the case of HBV; such a reduction cannot be confirmed for HCV and HIV. Consideration of the three viruses jointly confirms a reduction in the residual risk; we are unable to establish whether the evolution of the joint incidence rate has contributed to this reduction or whether it is due only to the shortening of window periods.

Red blood cell transfusion in surgery: an observational study of the trends in the USA from 2011 to 2016

Guidelines recommend restrictive red blood cell transfusion strategies. We conducted an observational study to examine whether the rate of peri-operative red blood cell transfusion in the USA had declined during the period from 01 January 2011 to 31 December 2016. We included 4,273,168 patients from all surgical subspecialties. We examined parallel trends in rates of the following: pre-operative transfusion; prevalence of bleeding disorders and coagulopathy; and minimally invasive procedures. To account for changes in population and procedure characteristics, we performed multivariable logistic regression to assess whether the risk of receiving a transfusion had declined over the study period. Clinical outcomes included peri-operative myocardial infarction, stroke and all-cause mortality at 30 days. Peri-operative red blood cell transfusion rates declined from 37,040/441,255 (8.4%) in 2011 to 46,845/1,000,195 (4.6%) in 2016 (p < 0.001) across all subspecialties. Compared with 2011, the corresponding adjusted OR (95%CI) for red blood cell transfusion decreased gradually from 0.88 (0.86-0.90) in 2012 to 0.51 (0.50-0.51) in 2016 (p < 0.001). Pre-operative red blood cell transfusion rates and the prevalence of bleeding disorders decreased, whereas haematocrit levels and the proportion of minimally invasive procedures increased. Compared with 2011, the adjusted hazard ratios (95%CI) in 2012 and 2016 were 0.96 (0.90-1.02) and 1.05 (0.99-1.11) for myocardial infarction, 0.91 (0.83-0.99) and 0.99 (0.92-1.07) for stroke and 0.98 (0.94-1.02) and 0.99 (0.96-1.03) for all-cause mortality. Use of peri-operative red blood cell transfusion declined from 2011 to 2016. This was not associated with an increase in adverse clinical outcomes.

Occult hepatitis B in kidney transplants recipients and donors from Western Mexico

BACKGROUND

Occult hepatitis B virus infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in serum and/or liver from HBsAg-negative subjects. Our aim was to determine OBI frequency in serum and genomic DNA in patients undergoing renal transplant and their cognate donors in a selected population from Western Mexico.

METHODS

Blood samples were obtained from 94 donors and their cognate recipients (188 participants) before kidney transplantation. Identification of HBV DNA was carried-out by nested (S-region) and semi-nested (Pol-region) PCR in both genomic and serum DNA samples from 188 participants at pre-surgical stage and from a subset of 73 recipients at three-month follow-up.

RESULTS

HBV-DNA was not detected in either genomic or serum DNA samples from recipients or donors prior to transplantation. After three-months of follow-up, 2 out of 73 (2.7%, 95% CI: 0.9-11.9%) recipients were positive to HBV-DNA (Pol-region) in genomic DNA samples using a high sensitivity Taq DNA polymerase.

CONCLUSIONS

OBI incidence in recipients of kidney transplant may be higher than previously recognized. Detection of HBV-DNA was higher in genomic DNA than in serum samples using a high sensitivity Taq DNA polymerase. To the best of our knowledge, this is the first report regarding this specific topic in Mexicans.

Anemia management in cancer patients with chronic kidney disease

Cancer and kidney disease are linked by causality and comorbidities. Observational data show an increased risk of malignancy as renal function declines. Erythropoietin stimulating agents (ESAs), which are the cornerstone therapy for anemia patients with chronic kidney disease and cancer, are associated with increased risks for cancer, cancer-related mortality, progression of disease, and thromboembolic events. This article examines the recently published guidelines for ESA use in cancer patients from the American Society of Clinical Oncology and American Society of Hematology and attempts to contextualize them to the care of patients with coexistent CKD, cancer, and anemia.

Verification of serum albumin elevating effect of cell-free and concentrated ascites reinfusion therapy for ascites patients: a retrospective controlled cohort study

Cell-free and concentrated ascites reinfusion therapy (CART) is frequently used to treat refractory ascites in Japan. However, its efficacy remains unclear. This controlled cohort study verified the serum albumin elevating effect of CART by comparisons with simple paracentesis. Ascites patients receiving CART (N = 88) or paracentesis (N = 108) at our hospital were assessed for the primary outcome of change in serum albumin level within 3 days before and after treatment. A significantly larger volume of ascites was drained in the CART group. The change in serum albumin level was +0.08 ± 0.25 g/dL in the CART group and −0.10 ± 0.30 g/dL in the paracentesis group (P < 0.001). The CART – paracentesis difference was +0.26 g/dL (95%CI +0.18 to +0.33, P < 0.001) after adjusting for potential confounders by multivariate analysis. The adjusted difference increased with drainage volume. In the CART group, serum total protein, dietary intake, and urine volume were significantly increased, while hemoglobin and body weight was significantly decreased, versus paracentesis. More frequent adverse events, particularly fever, were recorded for CART, although the period until re-drainage was significantly longer. This study is the first demonstrating that CART can significantly increase serum albumin level as compared with simple paracentesis. CART represents a useful strategy to manage patients requiring ascites drainage.

Usefulness of nucleic acid testing among negative HBs Ag blood donors in Egypt

INTRODUCTION

Hepatitis B viral infection has been transmitted from donors with HBV infections who have negative HBs Ag. Many countries have implemented nucleic acid testing (NAT) to screen donors with non- reactive HBs Ag for detection of HBV DNA and enhance safety of blood transfusion, while it is restricted to limited blood banks in Egypt.

OBJECTIVE

To evaluate the significance of NAT technology in detection of HBV DNA in the Egyptian blood donors with HBs Ag non- reactivity.

METHODS

The study included 36,584 collected blood samples from volunteer blood donors at the blood bank of Zagazig University Hospitals. Each specimen was tested for HBs Ag; non- reactive sera were further tested for qualitative detection of HBV-DNA by NAT testing. All positive HBV-DNA donors were tested for anti- HBc and anti- HBs by electro-chemiluminescence immunoassay and confirmed by quantitative RT-PCR.

RESULTS

Among 34,671 donors non-reactive to HBs Ag, 34,657 (99.96%) were tested negative for HBV- DNA and 14 specimens (0.04%) were positive for HBV via NAT testing. Among HBV NAT positive donors, HBs Ab reactive only in (2); HBc Ab reactive only in (3); HBs and HBc Abs reactive in (3) while HBs and HBc Ab non-reactive in (6). All tested sera 14 (100%) showed low viral load for HBV (<50 IU/ml) confirmed by RT- qPCR.

CONCLUSION

Our results highlighted the significance of the HBV NAT technique to reduce the potential risk of HBV transfusion-transmission and the critical need to enforce the usage of NAT technology in all blood banks in Egypt.

Recent and occult hepatitis B virus infections among blood donors in the United States

BACKGROUND

Characteristics of US blood donors with recent (RBI) or occult (OBI) hepatitis B virus (HBV) infection are not well defined.

METHODS

Donors with RBI and OBI were identified by nucleic acid and serologic testing among 34.4 million donations during 2009-2015. Consenting donors were interviewed and their HBV S-gene sequenced.

RESULTS

The overall rate of HBV-infected donors was 7.95 per 100,000; of these, 0.35 per 100,000 and 1.70 per 100,000 were RBI and OBI, respectively. RBI (n = 120) and OBI (n = 583) donors constituted 26% of all HBV-infected (n = 2735) donors. Detection of HBV DNA in 92% of OBI donors required individual donation nucleic acid testing. Donors with OBI compared to RBI were older (mean age, 48 vs 39 years; p < 0.0001) with lower median viral loads (9 vs. 529 IU/mL; p < 0.0001). A higher proportion of OBI than RBI donors were born or resided in an endemic country (39% vs. 5%; p = 0.0078). Seventy-seven percent of all RBI and OBI donors had multiple sex partners, an HBV-risk factor. Of 40 RBI and 10 OBI donors whose S gene was sequenced, 33 (83%) and 6 (60%), respectively, carried HBV subgenotype A2; 18 (55%) and 2 (33%), respectively, shared an identical sequence. Infection with 1 or more putative HBV-immune-escape mutants was identified in 5 (50%) of OBI but no RBI donors.

CONCLUSION

RBI and OBI continue to be identified at low rates, confirming the importance of comprehensive HBV DNA screening of US blood donations. HBV-infected donors require referral for care and evaluation and contact tracing; their HBV strains may provide important information on emergent genotypes.

Assessment of rapid diagnostic tests and fourth-generation Enzyme-Linked Immunosorbent Assays in the screening of Human Immunodeficiency and Hepatitis B virus infections among first-time blood donors in Libreville (Gabon)

BACKGROUND

Blood transfusion is a pathway for the transmission of blood-borne pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus (HBV) from donors to recipients in most countries in sub-Saharan Africa, including Gabon. The study aimed to compare the performance of four rapid diagnostic tests (RDTs: Alere DETERMINE, BIOSYNEX Exacto Pro HIV, MEDIFF HIV 1&2, and BIOSYNEX IMMUNOQUICK HBsAg) with results of 4th-generation immunoenzymatic assays COBAS 6000 e601 and EVOLIS BioRad for the detection of HIV and hepatitis B surface antigen (HBsAg) in blood donors in Libreville, Gabon.

METHODS

Reactive and nonreactive blood samples for HIV and HBsAg were selected using fourth-generation ELISA COBAS 6000 e601 and EVOLIS BioRad. The sensitivities of RDTs were calculated using Epi Info version 6.04dfr (CDC, Atlanta, USA).

RESULTS

Sensitivities for the detection of HIV in blood donors were 90.9% for Alere DETERMINE, 81.8% for BIOSYNEX Exacto Pro HIV, and 81.8% for MEDIFF HIV 1&2 Serum/sang Total Cassette compared with COBAS 6000 e601. The sensitivity of Alere DETERMINE compared to the semi-automated ELISA Bio-Rad for HIV detection was 65.6%. The sensitivity of BIOSYNEX IMMUNOQUICK HBsAg compared to ELISA tests for the detection of HBsAg was 78.0%. The specificity of all RDTs for the detection of HIV and HBsAg was 100%.

CONCLUSION

Alere DETERMINE HIV-1/2, MEDIFF HIV 1&2 Serum/sang Total Cassette, BIOSYNEX Exacto Pro HIV, and BIOSYNEX IMMUNOQUICK HBsAg are not recommended for determining whether donors qualify to donate blood because of their low sensitivity for the detection of HIV antibodies and HBsAg in blood donors in Gabon.

Significance of HBV NAT Among HBs Antigen-Negative Blood Donors in Saudi Arabia

Background

Bloodborne hepatitis B virus (HBV) transmission from asymptomatic donors with acute HBV infections who have undetectable surface antigen of HBV (HBsAg), or from donors with chronic infections in whom serological markers were not detected, could cause residual infections leading to relevant transfusion-transmitted infections (RTTIs). HBV nucleic acid testing (NAT) can detect HBV DNA in the HBsAg-negative and total hepatitis B core antibody (anti-HBc)-negative window period of infection and in chronic cases.

Objective

To assess the presence or absence of HBV DNA in blood donors with HBsAg negativity.

Methods

We collected 3014 blood specimens from volunteer blood donors at the blood bank of King Khalid University Hospital in Riyadh, Saudia Arabia. Specimens from each donor were tested for HBsAg, anti-HBc, and hepatitis B surface antibody (anti-HBs) by commercial immunoassays and for qualitative assessments of HBV-DNA by HBV-NAT testing.

Results

Of the 3014 donors, 7 (0.23%) tested positive for HBsAg and anti-HBc, 1 for HBsAg (0.03%) only, and of those 264 donors (8.8%) for anti-HBc. Of these last, 6.9% also tested positive for anti-HBs and 1.9% tested negative for anti-HBs. HBV-NAT testing was reactive in 75.0% of subjects who tested HBsAg positive, and nonreactive in 100% of subjects who tested anti-HBc positive/HBsAg negative (with or without anti-HBs). Among 2742 donors who tested seronegative, 1 specimen was determined to be reactive via HBV-NAT testing.

Conclusions

The frequency of HBV DNA in blood donors who tested seronegative was low. This finding may indicate the significance of the HBV NAT technique in reducing the residual risk of transfusion-transmitted HBV infection.

Blood donor testing for hepatitis B virus in the United States: is there a case for continuation of hepatitis B surface antigen detection?

BACKGROUND

In the United States, blood donor testing for hepatitis B surface antigen (HBsAg) was initiated in the early 1970s. More recently, testing for antibody to hepatitis B core antigen (anti-HBc) and hepatitis B virus (HBV) DNA have been added. The incidence of hepatitis B has been declining. This study reviews the current status of testing and questions the need for continuation of HBsAg testing.

STUDY DESIGN AND METHODS

From July 2011 to June 2015, a total of 22.4 million donations were serologically tested for HBsAg and anti-HBc and for HBV-DNA by nucleic acid testing (NAT). All reactive results were evaluated and a subset of donations that were either potential NAT yield (seronegative) or serologically positive but nonreactive by HBV NAT in minipools (MPs) of 16 were further evaluated by individual donation (ID)-NAT. Samples with detectable HBV DNA were defined as actively infected and considered potentially infectious.

RESULTS

Routine testing plus supplemental ID-NAT identified 2035 samples representing active infection including 1965 with anti-HBc, 1602 with HBsAg, and 1453 with HBV DNA by MP-NAT, for respective rates per hundred-thousand donations of 9.10, 8.78, 7.16, and 6.50, continuing the downward trend previously observed. There were 29 HBV DNA-yield samples (1:771,389), 35 HBsAg-yield samples (anti-HBc nonreactive), and 404 with occult hepatitis B infection. There were six samples with HBsAg and HBV DNA detectable only by ID-NAT in the absence of anti-HBc; additional testing was consistent with extremely low or negligible levels of DNA.

CONCLUSIONS

Point estimates of HBV infection rates among blood donors continue to decline, as do those for incidence and residual risk. Elimination of HBsAg screening would have negligible impact, with a risk less than 1 per 4 million donations.

Logistic regression with a continuous exposure measured in pools and subject to errors

In a multivariable logistic regression setting where measuring a continuous exposure requires an expensive assay, a design in which the biomarker is measured in pooled samples from multiple subjects can be very cost effective. A logistic regression model for poolwise data is available, but validity requires that the assay yields the precise mean exposure for members of each pool. To account for errors, we assume the assay returns the true mean exposure plus a measurement error (ME) and/or a processing error (PE). We pursue likelihood-based inference for a binary health-related outcome modeled by logistic regression coupled with a normal linear model relating individual-level exposure to covariates and assuming that the ME and PE components are independent and normally distributed regardless of pool size. We compare this approach with a discriminant function-based alternative, and we demonstrate the potential value of incorporating replicates into the study design. Applied to a reproductive health dataset with pools of size 2 along with individual samples and replicates, the model fit with both ME and PE had a lower AIC than a model accounting for ME only. Relative to ignoring errors, this model suggested a somewhat higher (though still nonsignificant) adjusted log-odds ratio associating the cytokine MCP-1 with risk of spontaneous abortion. Simulations modeled after these data confirm validity of the methods, demonstrate how ME and particularly PE can reduce the efficiency advantage of a pooling design, and highlight the value of replicates in improving stability when both errors are present.

Transfusion-Transmitted Infections: an Update on Product Screening, Diagnostic Techniques, and the Path Ahead

The mandated testing of blood components for infectious diseases, to prevent transfusion-transmitted infections (TTIs), began in the 1950s. Since then, changes in predonation questionnaires and advances in testing techniques have afforded more sensitive and specific tests for pathogens, in addition to allowing earlier detection. Given that these approaches have very low but detectable failure rates, the recent development and implementation of proactive pathogen reduction approaches is the new forefront of TTI prevention strategies. With globalization and the ability of pathogens to evolve rapidly, continuous redefining of testing standards and laboratory techniques is paramount for maintaining a safe blood supply.

Emergency Medicine Evaluation and Management of Anemia

Anemia is a common condition and is diagnosed on laboratory assessment. It is defined by abnormally low hemoglobin concentration or decreased red blood cells. Several classification systems exist. Laboratory markers provide important information. Acute anemia presents with symptoms owing to acute blood loss; chronic anemia may present with worsening fatigue, dyspnea, lightheadedness, or chest pain. Specific treatments depend on the underlying anemia and etiology. Iron is an alternative treatment for patients with microcytic anemia owing to iron deficiency. Hyperbaric oxygen is an option for alternative rescue therapy. Most patients with chronic anemia may be discharged with follow-up if hemodynamically stable.

Efforts Toward Elimination of Infectious Agents in Blood Products

The US blood supply has never been safer. This level of safety depends on a multifaceted approach including blood donor screening, sensitive infectious disease testing, and good manufacturing practice. However, risks remain for transfusion-transmitted infections due to bacterial contamination of platelets and emerging diseases. Thus, ongoing improvements in screening and testing are required. Newer pathogen reduction technologies have shown promise in further ameliorating the safety of the blood supply.

Donor blood screening and moral responsibility: how safe should blood be?

Some screening tests for donor blood that are used by blood services to prevent transfusion-transmission of infectious diseases offer relatively few health benefits for the resources spent on them. Can good ethical arguments be provided for employing these tests nonetheless? This paper discusses-and ultimately rejects-three such arguments. According to the 'rule of rescue' argument, general standards for cost-effectiveness in healthcare may be ignored when rescuing identifiable individuals. The argument fails in this context, however, because we cannot identify beforehand who will benefit from additional blood screening tests. On the 'imposed risk' argument, general cost-effectiveness standards do not apply when healthcare interventions impose risks on patients. This argument ignores the fact that imposing risks on patients is inevitable in healthcare and that these risks can be countered only within reasonable limits. Finally, the 'manufacturing standard' argument premises that general cost-effectiveness standards do not apply to procedures preventing the contamination of manufactured medical products. We contend that while this argument seems reasonable insofar as commercially manufactured medical products are concerned, publicly funded blood screening tests should respect the standards for general healthcare. We conclude that these particular arguments are unpersuasive, and we offer directions to advance the debate.

Sensitivity and specificity of a new automated system for the detection of hepatitis B virus, hepatitis C virus, and human immunodeficiency virus nucleic acid in blood and plasma donations

BACKGROUND

Use of nucleic acid testing (NAT) in donor infectious disease screening improves transfusion safety. Advances in NAT technology include improvements in assay sensitivity and system automation, and real-time viral target discrimination in multiplex assays. This article describes the sensitivity and specificity of cobas MPX, a multiplex assay for detection of human immunodeficiency virus (HIV)-1 Group M, HIV-2 and HIV-1 Group O RNA, HCV RNA, and HBV DNA, for use on the cobas 6800/8800 Systems.

STUDY DESIGN AND METHODS

The specificity of cobas MPX was evaluated in samples from donors of blood and source plasma in the United States. Analytic sensitivity was determined with reference standards. Infectious window periods (WPs) before NAT detectability were calculated for current donor screening assays.

RESULTS

The specificity of cobas MPX was 99.946% (99.883%-99.980%) in 11,203 blood donor samples tested individually (IDT), 100% (99.994%-100%) in 63,012 donor samples tested in pools of 6, and 99.994% (99.988%-99.998%) in 108,306 source plasma donations tested in pools of 96. Seven HCV NAT-yield donations and one seronegative occult HBV infection were detected. Ninety-five percent and 50% detection limits in plasma (IU/mL) were 25.7 and 3.8 for HIV-1M, 7.0 and 1.3 for HCV, and 1.4 and 0.3 for HBV. The HBV WP was 1 to 4 days shorter than other donor screening assays by IDT.

CONCLUSION

cobas MPX demonstrated high specificity in blood and source plasma donations tested individually and in pools. High sensitivity, in particular for HBV, shortens the WP and may enhance detection of occult HBV.

A general framework for the regression analysis of pooled biomarker assessments

As a cost-efficient data collection mechanism, the process of assaying pooled biospecimens is becoming increasingly common in epidemiological research; for example, pooling has been proposed for the purpose of evaluating the diagnostic efficacy of biological markers (biomarkers). To this end, several authors have proposed techniques that allow for the analysis of continuous pooled biomarker assessments. Regretfully, most of these techniques proceed under restrictive assumptions, are unable to account for the effects of measurement error, and fail to control for confounding variables. These limitations are understandably attributable to the complex structure that is inherent to measurements taken on pooled specimens. Consequently, in order to provide practitioners with the tools necessary to accurately and efficiently analyze pooled biomarker assessments, herein, a general Monte Carlo maximum likelihood-based procedure is presented. The proposed approach allows for the regression analysis of pooled data under practically all parametric models and can be used to directly account for the effects of measurement error. Through simulation, it is shown that the proposed approach can accurately and efficiently estimate all unknown parameters and is more computational efficient than existing techniques. This new methodology is further illustrated using monocyte chemotactic protein-1 data collected by the Collaborative Perinatal Project in an effort to assess the relationship between this chemokine and the risk of miscarriage. Copyright © 2017 John Wiley & Sons, Ltd.

Screening for Babesia microti in the U.S. Blood Supply

BACKGROUND

Babesia microti, a tickborne intraerythrocytic parasite that can be transmitted by means of blood transfusion, is responsible for the majority of cases of transfusion-transmitted babesiosis in the United States. However, no licensed test exists for screening for B. microti in donated blood. We assessed data from a large-scale, investigational product-release screening and donor follow-up program.

METHODS

From June 2012 through September 2014, we performed arrayed fluorescence immunoassays (AFIAs) for B. microti antibodies and real-time polymerase-chain-reaction (PCR) assays for B. microti DNA on blood-donation samples obtained in Connecticut, Massachusetts, Minnesota, and Wisconsin. We determined parasite loads with the use of quantitative PCR testing and assessed infectivity by means of the inoculation of hamsters and the subsequent examination for parasitemia. Donors with test-reactive samples were followed. Using data on cases of transfusion-transmitted babesiosis, we compared the proportions of screened versus unscreened donations that were infectious.

RESULTS

Of 89,153 blood-donation samples tested, 335 (0.38%) were confirmed to be positive, of which 67 (20%) were PCR-positive; 9 samples were antibody-negative (i.e., 1 antibody-negative sample per 9906 screened samples), representing 13% of all PCR-positive samples. PCR-positive samples were identified all through the year; antibody-negative infections occurred from June through September. Approximately one third of the red-cell samples from PCR-positive or high-titer AFIA-positive donations infected hamsters. Follow-up showed DNA clearance in 86% of the donors but antibody seroreversion in 8% after 1 year. In Connecticut and Massachusetts, no reported cases of transfusion-transmitted babesiosis were associated with screened donations (i.e., 0 cases per 75,331 screened donations), as compared with 14 cases per 253,031 unscreened donations (i.e., 1 case per 18,074 unscreened donations) (odds ratio, 8.6; 95% confidence interval, 0.51 to 144; P=0.05). Overall, 29 cases of transfusion-transmitted babesiosis were linked to blood from infected donors, including blood obtained from 10 donors whose samples tested positive on the PCR assay 2 to 7 months after the implicated donation.

CONCLUSIONS

Blood-donation screening for antibodies to and DNA from B. microti was associated with a decrease in the risk of transfusion-transmitted babesiosis. (Funded by the American Red Cross and Imugen; ClinicalTrials.gov number, NCT01528449 .).

Estimating the prevalence of multiple diseases from two-stage hierarchical pooling

Testing protocols in large-scale sexually transmitted disease screening applications often involve pooling biospecimens (e.g., blood, urine, and swabs) to lower costs and to increase the number of individuals who can be tested. With the recent development of assays that detect multiple diseases, it is now common to test biospecimen pools for multiple infections simultaneously. Recent work has developed an expectation-maximization algorithm to estimate the prevalence of two infections using a two-stage, Dorfman-type testing algorithm motivated by current screening practices for chlamydia and gonorrhea in the USA. In this article, we have the same goal but instead take a more flexible Bayesian approach. Doing so allows us to incorporate information about assay uncertainty during the testing process, which involves testing both pools and individuals, and also to update information as individuals are tested. Overall, our approach provides reliable inference for disease probabilities and accurately estimates assay sensitivity and specificity even when little or no information is provided in the prior distributions. We illustrate the performance of our estimation methods using simulation and by applying them to chlamydia and gonorrhea data collected in Nebraska. Copyright © 2016 John Wiley & Sons, Ltd.

Pediatric Patient Blood Management Programs: Not Just Transfusing Little Adults

Red blood cell transfusions are a common life-saving intervention for neonates and children with anemia, but transfusion decisions, indications, and doses in neonates and children are different from those of adults. Patient blood management (PBM) programs are designed to assist clinicians with appropriately transfusing patients. Although PBM programs are well recognized and appreciated in the adult setting, they are quite far from standard of care in the pediatric patient population. Adult PBM standards cannot be uniformly applied to children, and there currently is significant variation in transfusion practices. Because transfusing unnecessarily can expose children to increased risk without benefit, it is important to design PBM programs to standardize transfusion decisions. This article assesses the key elements necessary for a successful pediatric PBM program, systematically explores various possible pediatric specific blood conservation strategies and the current available literature supporting them, and outlines the gaps in the evidence suggesting need for further/improved research. Pediatric PBM programs are critically important initiatives that not only involve a cooperative effort between pediatric surgery, anesthesia, perfusion, critical care, and transfusion medicine services but also need operational support from administration, clinical leadership, finance, and the hospital information technology personnel. These programs also expand the scope for high-quality collaborative research. A key component of pediatric PBM programs is monitoring pediatric blood utilization and assessing adherence to transfusion guidelines. Data suggest that restrictive transfusion strategies should be used for neonates and children similar to adults, but further research is needed to assess the best oxygenation requirements, hemoglobin threshold, and transfusion strategy for patients with active bleeding, hemodynamic instability, unstable cardiac disease, and cyanotic cardiac disease. Perioperative blood management strategies include minimizing blood draws, restricting transfusions, intraoperative cell salvage, acute normovolemic hemodilution, antifibrinolytic agents, and using point-of-care tests to guide transfusion decisions. However, further research is needed for the use of intravenous iron, erythropoiesis-stimulating agents, and possible use of whole blood and pathogen inactivation. There are numerous areas where newly formed collaborations could be used to investigate pediatric transfusion, and these studies would provide critical data to support vital pediatric PBM programs to optimize neonatal and pediatric care.

Current concepts in the prevention of pathogen transmission via blood/plasma-derived products for bleeding disorders

The pathogen safety of blood/plasma-derived products has historically been a subject of significant concern to the medical community. Measures such as donor selection and blood screening have contributed to increase the safety of these products, but pathogen transmission does still occur. Reasons for this include lack of sensitivity/specificity of current screening methods, lack of reliable screening tests for some pathogens (e.g. prions) and the fact that many potentially harmful infectious agents are not routinely screened for. Methods for the purification/inactivation of blood/plasma-derived products have been developed in order to further reduce the residual risk, but low concentrations of pathogens do not necessarily imply a low level of risk for the patient and so the overall challenge of minimising risk remains. This review aims to discuss the variable level of pathogenic risk and describes the current screening methods used to prevent/detect the presence of pathogens in blood/plasma-derived products.