Rapid tests for detection of viral markers in blood transfusion

Double-Antigen Lateral Flow Immunoassay for the Detection of Anti-HIV-1 and -2 Antibodies Using Upconverting Nanoparticle Reporters

Rapid diagnostic tests (RDTs) are often used for the detection of anti-human immunodeficiency virus (HIV) antibodies in remote locations in low- and middle-income countries (LMIC) with low or limited access to central laboratories. The typical format of an RDT is a lateral flow assay (LFA) with visual interpretation prone to subjectivity. This risk of misinterpretation can be overcome with luminescent upconverting nanoparticle reporters (UCNPs) measured with a miniaturized easy-to-use reader instrument. An LFA with UCNPs for anti-HIV-1/2 antibodies was developed and the assay performance was evaluated extensively with challenging patient sample panels. Sensitivity (n = 145) of the UCNP-LFA was 96.6% (95% CI: 92.1–98.8%) and specificity (n = 309) was 98.7% (95% CI: 96.7–99.7%). Another set of samples (n = 200) was used for a comparison between the UCNP-LFA and a conventional visual RDT. In this comparison, the sensitivities for HIV-1 were 96.4% (95% CI: 89.8–99.3%) and 97.6% (95% CI: 91.6–99.7%), for the UCNP-LFA and conventional RDT, respectively. The specificity was 100% (95% CI: 96.4–100%) for both assays. The developed UCNP-LFA demonstrates the applicability of UCNPs for the detection of anti-HIV antibodies. The signal measurement is done by a reader instrument, which may facilitate automated result interpretation, archiving and transfer of data from de-centralized locations.

Seropositivity Load in Orthopedic Surgery at Tertiary Care Hospitals in North India - An Observational Study

BACKGROUND

Exposure to blood and blood-borne viruses is major concern for orthopedic surgeons and operation theater staff because of constant exposure to sharp instruments and bodily fluids. The objective of this study was to assess the burden of seropositive patients in the orthopedic department of tertiary care hospitals in North India.

MATERIALS AND METHODS

This retrospective study was carried out in author's institute on indoor patients admitted from January 2015 to December 2017. A total of 8914 patients were included in the study and relevant clinical data were collected for seropositivity of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) in patients admitted in the orthopedic emergency department. These patients were routinely tested for seropositivity before undergoing various surgical procedures.

RESULTS

A total of 8914 patients included in the study, out of which 7193 (80.7%) were male and 1721 (19.3%) were female. Out of total patients, 262 (2.9%) were found to be seropositive. Out of these patients, 31 (11.8%) were found to be positive for HIV, 190 (72.5%) for HCV, and 41(15.7%) for HBV. About 35.90% of patients with highest prevalence of seropositivity were truck drivers.

CONCLUSION

HIV, HBsAg, and HCV are common in this region with HCV infection being the major concern in Punjab. Screening for viral markers will help in adequate pre-operative planning, timely precautions, and immediate post-exposure prophylaxis in case of contact with blood or body fluids of seropositive patients.

Towards 2030 Target for Hepatitis B and C Viruses Elimination: Assessing the Validity of Predonation Rapid Diagnostic Tests versus Enzyme-linked Immunosorbent Assay in State Hospitals in Kaduna, Nigeria

Introduction:

Sub-Saharan Africa accounts for 25% of the estimated global 325 million people with chronic hepatitis B and C virus infections. Weak blood transfusion systems facilitate the spread of both hepatitis B and C virus infections. This is worsened by the absence of sustainable quality assurance programs and perennial shortage of sensitive screening kits. We aim to compare the validity of rapid diagnostic tests (RDTs) with the World Health Organization-recommended quality-assured enzyme-linked immunosorbent assay (ELISA) screening method for these viruses.

Materials and Methods:

We conducted a cross-sectional study on consecutive blood donor samples. Two hundred and sixty-four blood donor samples screened for hepatitis B and C viruses using RDTs were retested at a National blood transfusion service, Kaduna, Nigeria. Data were analyzed using OpenEpi version 3.01 to determine the sensitivity, specificity, and predictive values of RDTs versus ELISA.

Results:

The sensitivities of the RDTs at 95% confidence interval (CI) were low – 40% (19.8–64.3) and 50.0% (18.8–81.2) – for hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) antibody, respectively. The specificities and 95% CI were high – 99.9% (97.8–99.9) and 100.0% (98.5–100) for HBsAg and HCV antibody, respectively.

Conclusion:

Predonation RDTs screening of blood donor samples for hepatitis B virus and HCV in hospital donation units performed poorly compared to quality-assured ELISA screening in Kaduna. The risk of transmitting viral hepatitis through blood transfusion still exists. We recommend quality-assured ELISA screening of all donated units for HBsAg and HCV antibody to reduce the risk of these transfusion-transmitted infections.

Prevalence of Hepatitis B and C Viral Markers in Blood Donors Deferred from Donating Blood on the Basis of a History of Jaundice of Unknown Origin

BACKGROUND AND AIMS

The aim of the present study was to know the prevalence of viral hepatitis markers among blood donors deferred on the basis of a history of jaundice of unknown origin and to predict the impact of this deferral on blood safety.

METHODS

Observational study included 200 blood donors deferred on the basis of a history of jaundice of unknown origin and carried out serology and Individual Donation Nucleic Acid Testing (ID-NAT) for hepatitis B and hepatitis C.

RESULTS

Five (2.5%) out of 200 blood donors deferred on the basis of history of jaundice were reactive on ELISA. Three out of five were reactive for HBsAg; whereas two for anti-HCV antibodies. Out of the 12 ID-NAT initial reactive, 10 samples discriminated on further testing; 4 for HBV, 5 for HCV and 1 was co-infection (HBV + HCV). The odds of being picked up as sero reactive on ELISA was 2.53 (95% CI; 1.04-6.19) and being picked up as ID-NAT yield was 13.08 (95% CI; 5.29-32.37) in donors deferred on a history of jaundice of unknown origin as compared to selected donors without a history of jaundice, with the difference in means achieving statistically significance at P = 0.03 and <0.001 respectively.The potential of deferral on a history of jaundice of unknown origin has a capacity to interdict 2-3 HBV and/or HCV reactive blood donors on serology and 5 HBV and/or HCV reactive blood donors on ID-NAT from entering the quarantine blood supply per 100 donors.

CONCLUSION

The findings of the present study support that a deferral for a history of jaundice of unknown origin after attaining the age of 12 years in the present scenario of transfusion transmissible infectious disease screening in India.

Diagnostic accuracy of blood centers in the screening of blood donors for viral markers

Introduction

Blood transfusion still remains a life saving intervention in almost all healthcare facilities worldwide. Screening of blood donors/blood units is done in almost every blood bank facility before the blood units/blood components are transfused to prevent transfusion-transmissible infections. The kind of testing kits or the methods used by a facility and the technical expertise of the personnel greatly affects the screening results of a facility. This study was aimed at evaluating the diagnostic accuracy of five hospital-based blood bank testing facilities (Komfo Anokye Teaching Hospital KNUST, Kwame Nkrumah University of Science and Technology, Agogo, Bekwai and Sunyani) that used rapid immunochromatograhic assays (RIA) in screening blood donors/blood units in Ghana.

Methods

Blood samples (300) from the five testing facilities and their screening results for hepatitis B surface antigen (HBsAg), antibodies to hepatitis C virus (HCV) and human immunodeficiency virus (HIV) using RIAs were obtained. All the samples were then analysed for the three viral markers using 3^rd generational enzyme linked immunosorbent assay (ELISA) kit as the gold standard.

Results

The mean false positive for HBsAg was 2.2% with Bekwai testing facility having the highest of 4.4%. For HCV, the mean false positive was 2.8% with Agogo and Bekwai testing facilities having the highest of 8.7% respectively. For HIV screening, the mean false positive was 11.1% with Bekwai testing facility having the highest of 28.0%. The mean false negative for the facilities were 3.0% for HBV, 75.0% for HCV and 0.0% for HIV with KATH having the highest of 6.3% for HBV, Bekwai having the highest of 100% for HCV and no facility showing false negative for HIV. Mean sensitivity of the screening procedure for the facilities was 97.0%, 25.0% and 100.0% whilst the mean specificity was 97.8%, 97.2% and 88.9% for HBV, HCV and HIV respectively. Statistical comparison among the testing facilities showed no significant differences among the various testing centres for HBV screening; however, significant differences were obtained for HCV and HIV screening.

Conclusion

This study has shown that there is no standardised screening procedure for blood bank testing facilities in the country. There is therefore an urgent need for an internal and external control body to oversee screening procedures in blood banks across the country.

The use of rapid diagnostic tests for transfusion infectious screening in Africa: a literature review

Infectious risk associated with blood transfusion remains a major public health challenge in Africa, where prevalence rates of the major transfusion-transmissible infections (ie, hepatitis B, hepatitis C, human immunodeficiency virus, and syphilis) are among the highest in the world. Resource-limited blood services often operate with minimal predonation screening safeguards, prompting exclusive reliance on laboratory testing to mitigate infectious risk. Transfusion screening with rapid diagnostic tests (RDTs) has been adopted in areas that lack the capacity to support the routine use of more sophisticated technologies. However, uncertainty surrounding the performance of some RDTs in the field has spurred debate regarding their application to blood donation screening. Our review of the literature identified 17 studies that evaluated RDTs for the infectious screening of blood donors in Africa. The review highlights the variable performance of available RDTs and the importance of their use in a quality-assured manner. Deficiencies in performance observed with some RDTs underscore the need to validate test kits prior to use under field conditions with locally acquired samples. Suboptimal sensitivities of some available tests, specifically hepatitis B virus rapid assays, question their suitability in single-test algorithms, particularly in high-prevalence regions. Although RDTs have limitations, many of which can be addressed through improved training and quality systems, they are frequently the only viable option for infectious screening in resource-poor African countries. Therefore, additional studies and specific guidelines regarding the use of RDTs in the context of blood safety are needed.

Development of a microchip Europium nanoparticle immunoassay for sensitive point-of-care HIV detection

Rapid, sensitive and specific diagnostic assays play an indispensable role in determination of HIV infection stages and evaluation of efficacy of antiretroviral therapy. Recently, our laboratory developed a sensitive Europium nanoparticle-based microtiter-plate immunoassay capable of detecting target analytes at subpicogram per milliliter levels without the use of catalytic enzymes and signal amplification processes. Encouraged by its sensitivity and simplicity, we continued to miniaturize this assay to a microchip platform for the purpose of converting the benchtop assay technique to a point-of-care test. It was found that detection capability of the microchip platform could be readily improved using Europium nanoparticle probes. We were able to routinely detect 5 pg/mL (4.6 attomoles) of HIV-1 p24 antigen at a signal-to-blank ratio of 1.5, a sensitivity level reasonably close to that of microtiter-plate Europium nanoparticle assay. Meanwhile, use of the microchip platform effectively reduced sample/reagent consumption 4.5 fold and shortened total assay time 2 fold in comparison with microtiter plate assays. Complex matrix substance in plasma negatively affected the microchip assays and the effects could be minimized by diluting the samples before loading. With further improvements in sensitivity, reproducibility, usability, assay process simplification, and incorporation of portable time-resolved fluorescence reader, Europium nanoparticle immunoassay technology could be adapted to meet the challenges of point-of-care diagnosis of HIV or other health-threatening pathogens at bedside or in resource-limited settings.

Evaluation of the performance of four methods for detection of hepatitis B surface antigen and their application for testing 116,455 specimens

Hepatitis B surface antigen (HBsAg) is a crucial serum marker for the diagnosis of hepatitis B virus (HBV) infection. It is imperative to compare test results from different detection methods based on different principles. Four methods, chemiluminescent microparticle immunoassay (CMIA), electrochemiluminescent immunoassay (ECLIA), enzyme-linked immunosorbent assay (ELISA) and golden immunochromato-graphic assay (GICA) were applied to test the HBsAg level in 250 specimens. According to the EP12-A2 and EP15-A2 documents from Clinical and Laboratory Standards Institute (CLSI), the concentration at which repeated results are 50% positive (C50) of HBsAg detected by CMIA, ECLIA, ELISA and GICA was 0.05, 0.08, 0.15 and 15.0IU/ml, respectively. When the detection concentration of HBsAg was 0.5IU/ml, the imprecision degree of CMIA, ECLIA and ELISA was 8.1%, 5.9% and 14.9% respectively. When detecting high HBsAg level (≥20.0IU/ml) and HBsAg negative specimens, the consistency of the four methods was high, while for the low level (0.05-20.0IU/ml), the consistency was poor (except for the CMIA and ECLIA, P<0.05). When evaluation of the four methods in qualitative diagnosis of HBsAg level in the 116,455 specimens, there was no significant discrepancy among CMIA, CMIA and ECLIA, however, GICA was significantly different from the other 3 methods. Compared with CMIA, the false negative rate of ECLIA, ELISA and GICA was 0.2%, 1.3% and 12.3% respectively. In conclusion, GICA was only suitable for the preliminary screening of HBsAg positive individuals and ELISA can be applied to the qualitative diagnosis of HBsAg. Both CMIA and ECLIA were suitable for the quantitative determination of HBsAg.

Use of quality rapid diagnostic testing for safe blood transfusion in resource-limited settings

Blood safety in sub-Saharan Africa is jeopardized by multiple and diverse factors, including the predominance of high-risk family/replacement donors and the high prevalence of transfusion-transmissible infections (TTIs). Thus, stringent diagnostic strategies are vital. Western blotting is costly and technically demanding, and nucleic acid testing technologies, which have been reported to reliably reduce the rate of TTI, are not available in resource-limited settings. Therefore, there is a need for reliable and affordable testing alternatives in these settings. Rapid diagnostic testing has been widely adopted in developing countries, but, for effectiveness in blood safety, highly sensitive tests and the strict selection of low-risk blood donors are indispensable. Although the pre-serological window period remains a source of residual risk for transmission of TTIs during blood transfusion, the combination antigen-antibody rapid tests could contribute significantly to shortening the window period. Thus, despite its limitations, rapid diagnostic testing continues to contribute significantly to blood safety, as a cost-effective means of enhancing screening for TTIs and reducing their transmission in resource-limited rural settings.

Simultaneous triple point-of-care testing for HIV, syphilis and hepatitis B virus to prevent mother-to-child transmission in India

An innovative simultaneous triple point-of-care (STPOC) screening strategy for syphilis, hepatitis B and HIV with Determine(®) tests was offered to pregnant women presenting for antenatal care and evaluated for feasibility and preference in rural India. Of 1066 participants approached, 1046 consented, of which 1002 (96.0%) completed the strategy. Only 9% reported any history of testing in their current pregnancy. With STPOC screening, 989 women (98.7%) tested negative and 13 had preliminary positive results for infection. The total time taken was 45 minutes per participant. Mothers and infants were provided prophylaxis/treatment for HIV, syphilis and hepatitis B, with interventions initiated within 3-5 days. STPOC was preferred by 99.3% (95%CI: 98.8-99.8%) of participants, facilitated early simultaneous screening for the three infections, timely initiation of prophylaxis/treatment and was feasible in this rural setting. These data suggest that multiplexed STPOC screening for syphilis, hepatitis B and HIV in pregnancy would be desirable for women in rural India.

External financial aid to blood transfusion services in sub-Saharan Africa: a need for reflection

Jean-Pierre Allain and colleagues argue that, while unintended, the foreign aid provided for blood transfusion services in sub-Saharan Africa has resulted in serious negative outcomes, which requires reflection and rethinking.

Seroprevalence of transfusion-transmissible infections and evaluation of the pre-donation screening performance at the Provincial Hospital of Tete, Mozambique

Background

The World Health Organization recommends universal and quality-controlled screening of blood donations for the major transfusion-transmissible infections (TTIs): human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis. The study objectives were to determine the seroprevalence of these TTIs among blood donors at the Provincial Hospital of Tete, Mozambique, and to assess the local pre-donation screening performance.

Methods

All consenting voluntary and replacement candidate blood donors were consecutively included from February to May 2009. Sera of all candidates, independent of deferral by questionnaire, were submitted to screening with quality-assured rapid or simple assays for HIV, HBV surface antigen (HBsAg), HCV and syphilis. Assays locally used by the blood bank for HBV and syphilis screening were run in parallel to quality-assured external assays supplied during the study, and all discordant samples were submitted to confirmation testing in reference laboratories in Mozambique and Belgium.

Results

Of 750 consenting candidates (50.5% of voluntary donors), 71 (9.5%) were deferred by the questionnaire, including 38 specifically because of risk behavior for TTI. Of the 679 non-deferred candidates, 127 (18.7%) had serological confirmation of at least one TTI, with a lower prevalence in voluntary than in replacement donors (15.2% versus 22.4%, p = 0.016). Seroprevalence of HIV, HBsAg and syphilis infections was 8.5%, 10.6 % and 1.2%. No confirmed HCV infection was found. Seroprevalence of TTIs was similar in the 38 candidates deferred for TTI risk as in the non-deferred group, except for HBsAg (26.3 % versus 10.6 %; p = 0.005). The local assays used for HBV and syphilis had sensitivities of 98.4% and 100% and specificities of 80.4% and 98.8% respectively. This resulted in the rejection of 110 of the 679 blood donations (16.2%) because of false positive results.

Conclusions

The seroprevalence of TTIs after questionnaire screening is high in Tete, Mozambique, but HCV infection does not appear as a major issue. The questionnaire did not exclude effectively HIV-infected donor candidates, while the locally used assays led to unnecessary rejection of many safe donations. A contextualized questionnaire and consistent use of quality-assured assays would considerably improve the current screening procedure for blood donation.

HIV diagnostics: challenges and opportunities

Accurate HIV diagnostic testing continues to pose challenges, but there are also opportunities for assay performance improvements in key areas for specific intended-use settings. The genetic diversity of HIV can result in false and discordant results in assays that fail to detect new variant strains. The use of antiretroviral therapies has resulted in drug-resistant variants that require monitoring by sequencing and genotyping methods. Nucleic acid testing is the most sensitive and reliable platform for detection, but it is costly and limited to centralized testing facilities, making implementation difficult in resource-limited settings where HIV has hit the hardest. Rapid antibody tests suitable for point-of-care use are becoming more accessible in resource-limited settings, but these tests may not detect HIV during the acute infection stage. Emerging antigen/antibody combination assays are viable alternatives to nucleic acid testing for diagnosis of recent infections. Although patient monitoring (e.g., via CD4+ T-cell count and viral load determination) and infant diagnoses still rely on clinical laboratory-based testing, point-of-care options are being developed. There are other technical challenges to HIV diagnostic testing and emerging biodetection technologies that may be able to address them, but they are not yet proven.

Risk assessment and cost-effectiveness/utility analysis

Decision-makers at all levels of public health and transfusion medicine have always assessed the risks and benefits of their decisions. Decisions are usually guided by immediately available information and a significant amount of experience and judgment. For decisions concerning familiar situations and common problems, judgment and experience may work quite well, but this type of decision process can lack clarity and accountability. Public health challenges are changing as emerging diseases and expensive technologies complicate the decision-makers' task, confronting the decision-maker with new problems that include multiple potential solutions. Decisions regarding policies and adoption of technologies are particularly complex in transfusion medicine due to the scope of the field, implications for public health, and legal, regulatory and public expectations regarding blood safety. To assist decision-makers, quantitative risk assessment and cost-effectiveness analysis are now being more widely applied. This set of articles will introduce risk assessment and cost-effectiveness methodologies and discuss recent applications of these methods in transfusion medicine.

Evaluation of a new hepatitis B virus surface antigen rapid test with improved sensitivity

A new rapid immunochromatographic assay based on the signal amplification system (SAS) has been developed by Diagnostics for the Real World (Europe) Ltd. for the detection of hepatitis B virus surface antigen (HBsAg) in plasma or serum specimens. The SAS format features enhanced sensitivity as a result of an increased binding valence of the detector molecules. We have now evaluated the performance of the new HBsAg rapid test (DRW-HBsAg) in comparison with a well-established commercial rapid test (Determine HBsAg; previously from Abbott Laboratories; now from Inverness Medical Innovations) and with a CE-marked enzyme immunoassay (EIA) (Hepanostika HBsAg Ultra; BioMérieux) as the gold standard. Testing of serially diluted in-house HBsAg-positive samples, the World Health Organization standard, and sensitivity and reference panels yielded an analytical sensitivity for the DRW test of 0.2 to 0.8 IU/ml across HBsAg serotypes. Evaluation with eight commercially available seroconversion panels showed that the DRW-HBsAg test detected HBsAg an average of 6.1 days (range, 3 to 8 days) earlier than the Determine assay (P = 0.0078). Test sensitivity was also examined with two low-titer HBsAg EIA-positive panels in Beijing, China. Whereas 100% of these samples were detected by the DRW-HBsAg test, only 15.0% (P < 0.0001) and 87.3% (P < 0.0001), respectively, were detected by the Determine HBsAg test. The performance of the DRW-HBsAg test was further evaluated with samples determined to be HBsAg positive or negative by the EIA in Conakry, Guinea, and Beijing, China. No significant difference in sensitivity between the DRW and Determine tests was apparent with the HBsAg EIA-reactive samples from Guinea (96.7% versus 94.4%, respectively) or China (99.46 versus 98.92%, respectively). The specificity of the Determine HBsAg test was slightly higher than that of DRW-HBsAg test (100 versus 99.2%, respectively) with samples from EIA-negative blood donors in China. In conclusion, the new DRW HBsAg rapid test is more sensitive than the Determine HBsAg test and is suitable for diagnostic and blood screening in resource-limited settings.

Protective effect of HLA-B57 on HCV genotype 2 infection in a West African population

Recovery from Hepatitis C virus (HCV) infection is considered infrequent (<20%) in western populations but reaches 50% in West Africa where genotype 2 infection is predominant. To investigate the role of cellular immune responses and host genetics in this phenomenon, samples from 104 Ghanaian blood donors reactive with anti-HCV assays were collected between 2000 and 2005. HCV antibody was confirmed by Western blot using genotype 2 recombinant core, E2 and NS3 proteins. Viral load and genotype were determined. Samples were stratified into 37 chronic, 35 recovered infections and 32 false positive. Eighty-one percentage of subjects with chronic infection (RNA positive) carried genotype 2 HCV. Cellular immune response was investigated in 35 frozen peripheral blood mononuclear cell (PBMC) samples suitable for interferon-gamma ELISPOT assay. Twelve out of 24 confirmed recovered, 1 out of 5 chronically infected and none of the 6 false-positive controls reacted to recombinant proteins. HLA-A, -B and -DR types were determined by DNA methodology. HLA-B*57 was significantly more frequent in the group which had recovered from HCV infection compared with chronically infected subjects (P = 0.0053, OR = 8.02). In conclusion, it is hypothesized that the dominance of genotype 2 HCV strains may be an important factor explaining the high rate of recovery from HCV infections in Ghana via an efficient contribution of HLA-B*57 which is relatively frequent in the population.

Improving the safety of the blood supply in Ecuador through external performance evaluation of serological screening of blood donors

BACKGROUND

The Ecuadorian National Blood System collects approximately 100 000 units of blood per year. Screening for infectious agents is conducted by 23 autonomous blood services using different methodologies and reagents.

OBJECTIVES

To evaluate the performance of serology testing by laboratories of the Ecuadorian National Blood Bank System.

STUDY DESIGN

Four proficiency panels were distributed between April 2003 and December 2004 containing samples that were characterized as either reactive or non-reactive for hepatitis B surface antigen (HBsAg), antibodies against hepatitis C virus (HCV), and antibodies against human immunodeficiency virus (HIV). Laboratories were classified according to the volume of blood units processed per year, as small (<5000), medium (5000-12000) and large (>12000).

RESULTS

Large and medium blood services consistently obtained better results than small ones. All of the 37 anti-HIV antibody false negative results and all of the 20 HBsAg false negative results were reported by small laboratories. False negative results were associated with the use of rapid tests. Laboratories using rapid tests and certain lots of an enzyme-linked immunosorbent assay (ELISA) failed to detect HCV reactive sera in December 2004.

CONCLUSION

The high number of incorrect results in most small blood services indicates serious weaknesses in blood screening that require urgent corrective action. The National Blood System has implemented on-site audits, training, technical assistance, and increased oversight. The long-term proposal is to centralize blood testing in two large blood centers. The results presented here underline the importance of strengthening the regulatory framework and oversight in Ecuador and highlight the role of external performance evaluation programs for blood safety improvement.