Validity of the rapid strip assay test for detecting HBsAg in patients admitted to hospital in Uganda

Smartphone-Based Dual-Channel Immunochromatographic Test Strip with Polymer Quantum Dot Labels for Simultaneous Detection of Cypermethrin and 3-Phenoxybenzoic Acid

Currently, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-MS (LC-MS) are the primary methods used to detect pesticides and their metabolites for biomonitoring of exposure. Although GC-MS and LC-MS can provide accurate and sensitive measurements, these techniques are not suitable for point-of-care or in-field biomonitoring applications. The objective of this work is to develop a smartphone-based dual-channel immunochromatographic test strip (ICTS) for on-site biomonitoring of exposure to cypermethrin by simultaneous detection of cypermethrin and its metabolite, 3-phenoxybenzoic acid (3-PBA). Polymer carbon dots (PCDs) with ultrahigh fluorescent brightness were synthesized and used as a signal amplifier in ICTS assay. Cypermethrin (a representative pyrethroid pesticide) and its major metabolite 3-PBA were simultaneously detected to provide more comprehensive analysis of cypermethrin exposure. After competitive immunoreactions between the target sample and the coating antigens preloaded on the test line, the tracer antibody (PCD-conjugated antibody) was quantitatively captured on the test lines. The captured PCDs were inversely proportional to the amount of the target compound in the sample. The red fluorescence on the test line was then recorded using a smartphone-based device capable of conducting image analysis and recording. Under optimal conditions, the sensor showed excellent linear responses for detecting cypermethrin and 3-PBA ranging from 1 to 100 ng/mL and from 0.1 to 100 ng/mL, respectively, and the limits of detection were calculated to be ∼0.35 ng/mL for cypermethrin and ∼0.04 ng/mL for 3-PBA. The results demonstrate that the ICTS device is promising for accurate point-of-care biomonitoring of pesticide exposure.

An Automated, Quantitative, and Multiplexed Assay Suitable for Point-of-Care Hepatitis B Virus Diagnostics

Hepatitis B virus (HBV) infection has a global reach with high prevalence in resource-limited areas like China and Africa. HBV patients in these areas have limited access to the currently used, costly HBV assays, which are performed in centralized clinical laboratories using single-plexed assays with bulky and expensive instruments. We aim to overcome these limitations by developing a simple and affordable HBV diagnostic platform to allow for timelier diagnosis and intervention of HBV infection. Using giant magnetoresistive (GMR) biosensor chips, we developed an automated and multiplexed quantitative platform for the measurement of a panel of HBV serology markers, including HBV “e” antigen (HBeAg), HBV surface antigen (HBsAg), and the antibody against HBsAg (anti-HBs). Our assay platform was able to detect each HBV marker with high specificity and sensitivity (with three orders of magnitude in dynamic range for each marker). Blinded analysis of HBV patient sera showed excellent correlation between our multiplexed quantitative HBsAg results and the qualitative results obtained using FDA-approved immunoassays, as well as those obtained using quantitative, single-plexed, enzyme-linked immunosorbent assays (ELISAs). The portable, automated, multiplexed, quantitative HBV serology assay platform we designed shows great promise as a more accessible alternative for HBV screening, diagnosis, and treatment monitoring.

Diagnostic accuracy of tests to detect hepatitis B surface antigen: a systematic review of the literature and meta-analysis

BACKGROUND

Chronic Hepatitis B Virus (HBV) infection is characterised by the persistence of hepatitis B surface antigen (HBsAg). Expanding HBV diagnosis and treatment programmes into low resource settings will require high quality but inexpensive rapid diagnostic tests (RDTs) in addition to laboratory-based enzyme immunoassays (EIAs) to detect HBsAg. The purpose of this review is to assess the clinical accuracy of available diagnostic tests to detect HBsAg to inform recommendations on testing strategies in 2017 WHO hepatitis testing guidelines.

METHODS

The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using 9 databases. Two reviewers independently extracted data according to a pre-specified plan and evaluated study quality. Meta-analysis was performed. HBsAg diagnostic accuracy of rapid diagnostic tests (RDTs) was compared to enzyme immunoassay (EIA) and nucleic-acid test (NAT) reference standards. Subanalyses were performed to determine accuracy among brands, HIV-status and specimen type.

RESULTS

Of the 40 studies that met the inclusion criteria, 33 compared RDTs and/or EIAs against EIAs and 7 against NATs as reference standards. Thirty studies assessed diagnostic accuracy of 33 brands of RDTs in 23,716 individuals from 23 countries using EIA as the reference standard. The pooled sensitivity and specificity were 90.0% (95% CI: 89.1, 90.8) and 99.5% (95% CI: 99.4, 99.5) respectively, but accuracy varied widely among brands. Accuracy did not differ significantly whether serum, plasma, venous or capillary whole blood was used. Pooled sensitivity of RDTs in 5 studies of HIV-positive persons was lower at 72.3% (95% CI: 67.9, 76.4) compared to that in HIV-negative persons, but specificity remained high. Five studies evaluated 8 EIAs against a chemiluminescence immunoassay reference standard with a pooled sensitivity and specificity of 88.9% (95% CI: 87.0, 90.6) and 98.4% (95% CI: 97.8, 98.8), respectively. Accuracy of both RDTs and EIAs using a NAT reference were generally lower, especially amongst HIV-positive cohorts.

CONCLUSIONS

HBsAg RDTs have good sensitivity and excellent specificity compared to laboratory immunoassays as a reference standard. Sensitivity of HBsAg RDTs may be lower in HIV infected individuals.

[Occult hepatitis B reactivation in a patient with homozygous sickle cell disease: clinical case and literature review]

Occult Hepatitis B corresponds to the presence of hepatitis B virus-deoxyribonucleic acid (HBV-DNA) in serum and/or in liver of a patient despite HBsAg negativity. Clinically, it is usually asymptomatic. Its reactivation is rare and commonly occurs in immunosuppressed individuals. We report the case of a 21-year old patient from Senegal, with homozygous sickle cell disease, presenting with cholestatic jaundice. Laboratory tests showed reactivation of occult Hepatitis B. This study emphasizes the need to systematically investigate the presence of occult Hepatitis B in patients with sickle cell disease suffering from acute liver disease.

Hepatitis B serological markers and plasma DNA concentrations

Objectives:

To examine hepatitis B (HBV) serological markers and plasma DNA concentrations in a large group of untreated HBV/HIV-coinfected individuals in two sub-Saharan settings.

Design:

Baseline analysis of a randomized controlled trial.

Methods:

DART was a large trial of treatment monitoring practices in HIV-infected adults with advanced disease starting antiretroviral therapy at centres in Kampala or Entebbe, Uganda (n = 2317) and Harare, Zimbabwe (n = 999). HBV serological markers [antibody to HBV core antigen, HBV surface antigen (HBsAg), antibody to HBV surface antigen, HBV ‘e’ antigen (HBeAg), and antibody to hepatitis B ‘e’ antigen] and plasma HBV DNA viral load were measured retrospectively on stored baseline samples. Logistic regression was used to examine associations with baseline demographic and clinical factors.

Results:

The rate of HBsAg positivity was significantly higher in Zimbabwe than Uganda (12.2 vs. 7.7%, adjusted odds ratio = 1.54, P < 0.001) despite a similar prevalence of antibody to HBV core antigen (56.3 vs. 52.4%) in the two settings. Overall, HBsAg positivity was associated with male sex (adjusted odds ratio = 1.54, P < 0.001) but not with age, WHO disease stage, or CD4⁺ cell count. HBeAg was detected among 37% of HBsAg-positive patients, with higher rates among those with advanced WHO stage (P = 0.02). Also in HBsAg-positive patients, HBV DNA was undetectable in 21%, detectable but below the level of quantification in 14%, and quantifiable in 65%. A total of 96% of HBeAg-positive and 70% of HBeAg-negative patients had detectable HBV DNA; 92 and 28% of patients, respectively, had HBV DNA viral load more than 2000 IU/ml.

Conclusion:

High rates of HBV coinfection were observed, highlighting the importance of ensuring that coinfected patients receive an antiretroviral regimen, whether first-line or not, that is active against both viruses.

Screening and diagnosis of HBV in low-income and middle-income countries

HBV testing and diagnosis of HBV-related liver disease in low-income and middle-income countries differs substantially from that in developed countries in terms of access to resources and expensive technologies requiring highly specialized staff. For identification and classification of HBV infection, genomic amplification methods to detect and quantify HBV DNA are often nonexistent or available only in central laboratories of major cities. When samples from peripheral locations do arrive, delays in receiving results generate loss to follow-up. Testing is often limited to measurement of hepatitis B surface antigen (HBsAg), alanine aminotransferase levels, aspartate aminotransferase to platelet ratio index and hepatitis B e antigen (HBeAg) to determine indications for antiviral therapy (AVT). Utilization of AVT is limited by cost and availability, particularly when patients are not covered by health insurance. The natural history of HBV infection is influenced by genotypes B and C in East Asia, where decades of immune tolerance have led to mostly vertical transmission; in sub-Saharan Africa, where genotypes A1 and E predominate, infection is transmitted horizontally between young children, followed by a nonreplicative phase. In both regions, cirrhosis and hepatocellular carcinoma are common and would be considerably ameliorated by AVT. Implementation of the HBV vaccine since the 1990s in Asia and 2000s in Africa has decreased the incidence of HBV, but vaccine failure and insufficiently effective prevention remain concerning issues.

Limited Genetic Diversity of Hepatitis B Virus in the General Population of the Offin River Valley in Ghana

Hepatitis B virus (HBV) infections account for approximately 780,000 deaths per year, most of which occur in the developing world. Co-infection with HBV and hepatitis delta virus (HDV) may lead to the most severe form of viral hepatitis. In Ghana, knowledge on the prevalence of HBV and HDV in the general population is scanty and the few genetic analyses of the prevailing HBV genotypes are dating back more than a decade. In the present study, 1,323 serum samples from individuals living in a rural area (Offin river valley) of Ghana were analyzed for the presence of the hepatitis B surface antigen (HBsAg). Positive sera were subsequently tested for the presence of anti-HDV antibodies. A total of 107 (8%) sera were HBsAg positive with an 8.4% prevalence of anti-HDV antibodies among the HBsAg positives. Phylogenetic analysis based on HBV pre-S/S sequences, attributed all 52 typable samples to genotype E. All belonged to serotype ayw4. While 19 sequences clustered with those from a number of African countries, the other 33 formed a separate cluster distinguished by an intergroup mean distance of 1.5% from the pan-African HBV/E cluster. Successful implementation of HBV vaccination in the region was reflected by the low HBsAg carrier rate of 1.8% among children ≤11 years.

A Simple and Rapid Test-card Method to Detect Hepatitis B Surface Antigen and Antibody: Potential Application in Young Children and Infants

BACKGROUND

Hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) were conventionally determined by enzyme immunoassays. We aimed to apply a rapid, simple, and accurate method to detect HBsAg and its antibody.

METHODS

We collected 1463 serum samples from healthy volunteers, hepatitis B carriers, and children of HBsAg-positive mothers. The test card that we examined is a chromatographic immunoassay for the qualitative detection of either HBsAg or anti-HBs. We then compared the results of the test card to the results of the conventional enzyme-immunoassay method, which is regarded as a standard.

RESULTS

In the use of the test card to check HBsAg, the sensitivity was 88.8% and the specificity was 100%. The median hepatitis B virus viral load was significantly higher in the true-positive group [10(3.71) copies/mL (range, 10(2)-10(9.03) copies/mL)] than in the false-negative group [10(2) copies/mL (range, 10(2)-10(3.26) copies/mL)] (p = 0.005). In those who were younger than 2 years, the diagnostic accuracy of the HBsAg test card was 100%. Then, 1272 samples were tested for anti-HBs rapid test card. The sensitivity was 91.8% and the specificity was 96.5%. The median anti-HBs titer was significantly higher in the true-positive group (295.8 mIU/mL) than in the false-negative group (42.3 mIU/mL; p < 0.001).

CONCLUSION

Because of (1) the limited amount of blood sample required and (2) most of the young hepatitis B virus carriers having high viremia, and no concerns of false negativity, the test card is a good rapid screening tool for the detection of HBsAg and anti-HBs in pediatric group.

Are current screening protocols for chronic hepatitis B virus infection adequate?

Chronic hepatitis B virus (HBV) infection screening usually includes only HBV surface antigen (HBsAg) testing; HBV core and surface antibody (anti-HBc, anti-HBs) assays, indicating resolved infection and immunity, are not routinely performed. Yet, serum HBV DNA is measurable in approximately 10% of HBsAg-negative/anti-HBc-positive cases, representing occult HBV infection (OBI). Patient blood samples from 2 Veterans Affairs medical center look-back investigations were screened for HBV infection using HBsAg enzyme immunoassays. Supplementary testing included anti-HBc and anti-HBs enzyme immunoassays. For anti-HBc-positive samples, HBV DNA testing was performed. Background OBI prevalence was further estimated at these 2 facilities based on HBV serology testing results from 1999-2012. Finally, a literature review was performed to determine OBI prevalence in the published literature. Of 1887 HBsAg-negative cohort patients, 98 (5.2%) were anti-HBc positive/anti-HBs negative; and 175 (9.3%), anti-HBc positive/anti-HBs positive. Six of 273 were HBV DNA positive, representing 0.3% of the total tested and 2.2% who were anti-HBc positive/anti-HBs negative or anti-HBc positive/anti-HBs positive. Among 32,229 general population veterans at these 2 sites who had any HBV testing, 4/108 (3.7%) were HBV DNA positive, none of whom were part of the cohort. In 129 publications with HBsAg-negative patients, 1817/1,209,426 (0.15%) had OBI. However, excluding blood bank studies with greater than 1000 patients, the OBI rate increased to 1800/17,893 (10%). OBI is not rare and has implications for transmission and disease detection. HBsAg testing alone is insufficient for detecting all chronic HBV infections. These findings may impact blood donation, patient HBV screening, follow-up protocols for patients assumed to have cleared the infection, and initiation of immunosuppression in patients with distant or undetected HBV.

Evaluating HBsAg rapid test performance for different biological samples from low and high infection rate settings & populations

Background

Rapid tests (RTs) might have several advantages over standard laboratory procedures, increasing access to diagnosis, especially among vulnerable populations and/or those living in remote areas. The aim of this study was to evaluate the performance of RTs for the detection of hepatitis B virus surface antigen (HBsAg) in samples from different populations/settings.

Methods

Three RTs for HBsAg detection (Vikia® HBsAg, HBsAg Teste Rápido®, and Imuno-Rápido HBsAg®) and different biological specimens (serum, whole blood, and saliva) were evaluated. Analyses comprised a reference panel and samples from field studies targeting suspected cases of hepatitis B virus (HBV) (G I), individuals living in deprived areas (G II), and highly vulnerable individuals (G III). Enzyme immunoassay (EIA) was defined as the gold standard in this study. Reproducibility, repeatability, and cross-reactivity with other infectious agents such as dengue, immunodeficiency (HIV), and hepatitis C (HCV) viruses and T. pallidum were determined.

Results

For the reference panel, the sensitivity and specificity of all HBsAg RTs were higher than 93.00 %. G I presented the highest kappa values for all rapid assays using sera samples. When using serum, the sensitivity values were higher than 93.40 for G I, 60.00 % for G II and 66.77 % for G III, and the specificity values were higher than 99.50 for GI, 97.20 for G II and 99.10 % for G III for all tests. For whole blood samples & the Vikia® HBsAg assay, the best performance was achieved for GIII (k = 79.75 %). For saliva samples, the Imuno-Rápido HBsAg® assay showed the highest concordance values with EIA for G I (40.68 %) and G II (32.20 %). The reproducibility and repeatability of all RTs for serum and saliva were excellent, and the concordance between HBsAg EIAs and RTs using samples reactive with other infectious agents varied from 70.10 % to 100.00 %.

Conclusions

The overall performance of RTs for HBsAg in serum was high/moderately high for all groups, thereby promoting increased access to HBV diagnosis among vulnerable populations as well as samples from individuals in emergency settings or remote areas. Rapid tests for HBsAg using whole blood could be used in prevalence studies, though these assays should not be used for saliva samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1249-5) contains supplementary material, which is available to authorized users.

Update on hepatitis B and C virus diagnosis

Viral hepatitis B and C virus (HBV and HCV) are responsible for the most of chronic liver disease worldwide and are transmitted by parenteral route, sexual and vertical transmission. One important measure to reduce the burden of these infections is the diagnosis of acute and chronic cases of HBV and HCV. In order to provide an effective diagnosis and monitoring of antiviral treatment, it is important to choose sensitive, rapid, inexpensive, and robust analytical methods. Primary diagnosis of HBV and HCV infection is made by using serological tests for detecting antigens and antibodies against these viruses. In order to confirm primary diagnosis, to quantify viral load, to determine genotypes and resistance mutants for antiviral treatment, qualitative and quantitative molecular tests are used. In this manuscript, we review the current serological and molecular methods for the diagnosis of hepatitis B and C.

High prevalence of occult hepatitis B infection in an African urban population

Occult hepatitis B infection (OBI), the presence of low hepatitis B virus (HBV) deoxyribonucleic acid (DNA) levels in patients without detectable hepatitis B surface antigen (HBsAg), has significant implications for understanding the natural history of hepatitis B infection. We determined the prevalence of OBI in African patients using a sensitive polymerase chain reaction (PCR) assay and describe here the characteristics of OBI in an urban African hospital population. Routine serological testing as well as molecular studies were performed on sera from 314 patients who were part of a previous study from an urban hospital emergency room in Kampala, Uganda, detecting HBV DNA using a nested PCR with amplification of two regions of the HBV genome. HBV viral loads (VL) were determined by real-time PCR (rtPCR) and sequencing performed to determine HBV genotype and S gene mutations. Among 314 subjects tested, 50 (16%) had chronic HBV infection, 94 (30%) had detectable HBV DNA despite testing HBsAg negative (OBI), and 170 (54%) were not infected. VLs of OBI subjects were relatively low although 19 (20%) had VL exceeding 10(4)  IU ml(-) . Subjects with chronic HBV infection had a higher median VL compared to OBI patients (P < 0.001). All chronic HBV sequenced (10) and 83/89 OBI sequences were genotype A, the remaining six being genotype D. S-gene mutations were present in some but not all OBI patients (48%). OBI is more prevalent among African patients than previously thought. This may have implications for clinical management and transfusion-related HBV transmission.

Prevalence of HIV and hepatitis B virus co-infection in sub-Saharan Africa and the potential impact and program feasibility of hepatitis B surface antigen screening in resource-limited settings

BACKGROUND

Screening people living with HIV for hepatitis B virus (HBV) co-infection is recommended in resource-rich settings to optimize HIV antiretroviral therapy (ART) and mitigate HBV-related liver disease. This review examines the need, feasibility, and impact of screening for HBV in resource-limited settings (RLS).

METHODS

We searched 6 databases to identify peer-reviewed publications between 2007 and 2013 addressing (1) HIV/HBV co-infection frequency in sub-Saharan Africa (SSA); (2) performance of hepatitis B surface antigen (HBsAg) rapid strip assays (RSAs) in RLS; (3) impact of HBV co-infection on morbidity, mortality, or liver disease progression; and/or (4) impact of HBV-suppressive antiretroviral medications as part of ART on at least one of 5 outcomes (mortality, morbidity, HIV transmission, retention in HIV care, or quality of life). We rated the quality of individual articles and summarized the body of evidence and expected impact of each intervention per outcome addressed.

RESULTS

Of 3940 identified studies, 85 were included in the review: 55 addressed HIV/HBV co-infection frequency; 6 described HBsAg RSA performance; and 24 addressed the impact of HIV/HBV co-infection and ART. HIV/HBV frequency in sub-Saharan Africa varied from 0% to >28.4%. RSA performance in RLS showed good, although variable, sensitivity and specificity. Quality of studies ranged from strong to weak. Overall quality of evidence for the impact of HIV/HBV co-infection and ART on morbidity and mortality was fair and good to fair, respectively.

CONCLUSIONS

Combined, the body of evidence reviewed suggests that HBsAg screening among people living with HIV could have substantial impact on preventing morbidity and mortality among HIV/HBV co-infected individuals in RLS.

Prevention of materno-foetal transmission of hepatitis B in sub-Saharan Africa: the evidence, current practice and future challenges

Hepatitis B (HBV) infection is highly endemic in sub-Saharan Africa (SSA), where more than 8% of the population remain chronic HBV carriers. SSA has one of the highest HBV-related liver cancer rates in the world (CA Cancer J Clin, 55, 2005, 74) and HBV-related liver cancer is the most common cause of premature death in West Africa (Lancet Oncol, 9, 2008, 683; Hepatology, 39, 2004, 211). As such, HBV represents a significant global threat to health in the African continent. Most SSA countries have elected to vaccinate all children against HBV through the WHO-sponsored Expanded Program of Immunization and the current recommendation from WHO-AFRO is for birth-dose HBV vaccination to prevent maternal/child transmission (MFT) and early horizontal transmission of HBV. However, in Africa, HBV vaccine coverage remains low and HBV birth-dose vaccination has not been implemented. HBV transmission from mother to child in the early perinatal period therefore remains a significant contributor to the burden of HBV-related disease in SSA. This review explores the evidence for materno-foetal transmission of HBV in SSA, outlining current practice for HBV MFT prevention and identifying the significant challenges to implementation of HBV prevention in SSA.

Decompensated cirrhosis-related admissions in a large urban hospital in Uganda: prevalence, clinical and laboratory features and implications for planning patient management

BACKGROUND

Cirrhosis-related complications are a major cause of morbidity and mortality in areas where its risk factors are endemic.

OBJECTIVE

We determined the prevalence of decompensated cirrhosis among patients on the gastroenterology service of Mulago Hospital and described the clinical and laboratory features of these patients.

METHODS

All patients admitted to the unit were assessed and their diagnosis documented. Patients with cirrhosis had clinical features of decompensation recorded. History of alcohol consumption was taken and testing for hepatitis B surface antigen (HBsAg) and hepatitis C antibody (anti-HCV) performed.

RESULTS

Between September 2010 and January 2011, we enrolled 482 patients. The majority (53.7%) were male, overall median age 38 years. Decompensated cirrhosis was diagnosed in 85 (17.6%) patients. Of the 85 patients, 47 (55.3%) gave a history of alcohol intake, HBsAg was positive in 23 (27.1%) and anti-HCV in 3 (3.5%). Decompensation was defined by ascites among 81 (95.3%) patients, variceal bleeding in 31 (36.5%), encephalopathy in 20 (23.5%).

CONCLUSION

Cirrhosis is common in Mulago hospital presenting mainly with ascites and variceal bleeding. Aside from controlling causes of liver diseases, especially alcohol and hepatitis B virus infection, in the interim it is necessary to manage complications in patients who already have cirrhosis.

Diagnosis of alcohol misuse and alcoholic liver disease among patients in the medical emergency admission service of a large urban hospital in Sub-Saharan Africa; a cross sectional study

Introduction

Uganda is among the top ten consumers of alcohol worldwide though there is little data on alcohol related liver disease. We describe alcohol use, alcohol misuse, and alcoholic liver disease among adults at the emergency admission service of a large urban hospital in Uganda.

Methods

All adults who consented were prospectively evaluated for alcohol use by inquiry and alcohol misuse by the “Cutting down, Annoyance, Guilt and Eye-opener- CAGE” questionnaire. Alcohol related hepatocellular liver injury was assessed using aspartate aminotransferase, and alanine aminotransferase levels. A combination of CAGE score ≥2 and De Ritis ratio ≥2 defined alcoholic liver disease (ALD). Human Immunodeficiency Virus (HIV), and viral hepatitis B and C serologies were evaluated in all the patients. Descriptive and inferential statistics were generated to answer our research questions.

Results

Three hundred and eighty individuals consented and participated in the study. Among these, 46.8% acknowledged use of alcohol while 21% and 10% met the study definition of alcoholic misuse and alcoholic liver disease respectively. Both alcohol misuse and alcoholic liver disease was significantly associated (p-value ≤ 0.05) with male gender, region of origin, number of life time sexual partners and serum albumin below 3.5 mg/dl after univariate and multivariate analysis.

Conclusion

Alcohol misuse and alcoholic liver disease is frequent in this medical emergency unit. Our study suggests a link between alcohol misuse or alcoholic liver disease and male gender, region of origin, number of sexual partners, and serum albumin below 3.5mg/dl.

Multinational assessment of blood-borne virus testing and transfusion safety on the African continent

BACKGROUND

Failures of blood screening due to low test quality or poor laboratory technique increase the risk of transfusion-transmitted infections. For this reason, the World Health Organization has recommended a quality control (QC) system for African blood centers.

STUDY DESIGN AND METHODS

We conducted a cross-sectional research assessment of test performance at 51 blood centers in 17 African countries. A blinded, standardized panel containing 25 samples positive for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) and negative controls was tested by the centers using their operational infectious disease testing consisting of rapid tests, enzyme immunoassays (EIAs), or antigen-antibody EIAs. Nucleic acid testing was not performed.

RESULTS

The overall performances of the 42 assays were the lowest for hepatitis B surface antigen (75.6% sensitivity, 94.5% specificity), then for HCV (80.0% sensitivity, 98.1% specificity) and for HIV (81.4% sensitivity, 99.6% specificity). Poor sensitivity was driven by the use of rapid tests, which had sensitivities of 47.4% for HBV, 63.7% for HCV, and 72.4% for HIV. From a blood screening point of view, 321 (5.6%) infected units would have been transfused due to false-negative results. Assuming that those that were missed by rapid tests (84%) would have been detected by EIAs, 270 viral contaminations (92 HIV, 65 HCV, and 113 HBV) would have been avoided.

CONCLUSION

These results support the discontinuation of rapid tests and implementation of antigen-antibody EIAs whenever possible in Africa. This successful QC program highlights the need for promoting such periodic external quality assessment studies.

Epidemiology, Diagnosis, and Treatment of HIV-Associated Non-Hodgkin Lymphoma in Resource-Limited Settings

Lymphoma was a common complication of HIV infection in the pre-antiretroviral era, and the incidence of HIV-associated lymphoma has dropped dramatically since the introduction of combination antiretroviral therapy (cART) in resource-rich regions. Conversely, lymphoma is an increasingly common complication of HIV infection in resource-limited settings where the prevalence of HIV infection is high. Relatively little is known, however, about the true incidence and optimal treatment regimens for HIV-associated lymphoma in resource-poor regions. We review the epidemiology, diagnosis, and treatment of HIV-associated non-Hodgkin lymphoma in developing nations and highlight areas for further research that may benefit care in both settings. Examples include risk modification and dose modification of chemotherapy based on HIV risk factors, improving our understanding of the current burden of disease through national cancer registries, and developing cost-effective hematopathological diagnostic strategies to optimize care delivery and maximize use of available chemotherapy.

An integrated electrochemical device based on immunochromatographic test strip and enzyme labels for sensitive detection of disease-related biomarkers

A novel electrochemical biosensing device that integrates an immunochromatographic test strip and a screen-printed electrode (SPE) connected to a portable electrochemical analyzer was presented for rapid, sensitive, and quantitative detection of disease-related biomarker in human blood samples. The principle of the sensor is based on sandwich immunoreactions between a biomarker and a pair of its antibodies on the test strip, followed by highly sensitive square-wave voltammetry (SWV) detection. Horseradish peroxidase (HRP) was used as a signal reporter for electrochemical readout. Hepatitis B surface antigen (HBsAg) was employed as a model protein biomarker to demonstrate the analytical performance of the sensor in this study. Some critical parameters governing the performance of the sensor were investigated in detail. Under optimal conditions, this sensor was capable of detecting a minimum of 0.3 ng mL(-1) (S/N=3) HBsAg with a wide linear concentration range from 1 to 500 ng mL(-1). The sensor was further utilized to detect HBsAg spiked in human plasma with an average recovery of 91.3%. In comparison, a colorimetric immunochromatographic test strip assay (ITSA) was also conducted. The result shows that the SWV detection in the electrochemical sensor is much more sensitive for the quantitative determination of HBsAg than the colorimetric detection, indicating that such a sensor is a promising platform for rapid and sensitive point-of-care testing/screening of disease-related biomarkers in a large population.

Hepatitis B virus and sexual behavior in Rakai, Uganda

HIV and hepatitis B virus (HBV) co-infection poses important public health considerations in resource-limited settings. Demographic data and sera from adult participants of the Rakai Health Sciences Program Cohort in Southwestern Uganda were examined to determine HBV seroprevalence patterns in this area of high HIV endemicity prior to the introduction of anti-retroviral therapy. Commercially available EIAs were used to detect prevalent HBV infection (positive for HBV core antibody [anti-HBc] and/or positive HBV surface antigen [HBsAg]), and chronic infection (positive for HBsAg). Of 438 participants, 181 (41%) had prevalent HBV infection while 21 (5%) were infected chronically. Fourteen percent of participants were infected with HIV. Fifty three percent showed evidence of prevalent HBV infection compared to 40% among participants infected with HIV (P = 0.067). Seven percent of participants infected with HIV were HBsAg positive compared to 4% among participants not infected with HIV (P = 0.403). The prevalence of prevalent HBV infection was 55% in adults aged >50 years old, and 11% in persons under 20 years. In multivariable analysis, older age, HIV status, and serologic syphilis were significantly associated with prevalent HBV infection. Transfusion status and receipt of injections were not significantly associated with HBV infection. Contrary to expectations that HBV exposure in Uganda occurred chiefly during childhood, prevalent HBV infection was found to increase with age and was associated sexually transmitted diseases (HIV and syphilis.) Therefore vaccination against HBV, particularly susceptible adults with HIV or at risk of HIV/STDs should be a priority.

Low frequency of liver enzyme elevation in HIV-infected patients attending a large urban treatment centre in Uganda

Liver enzyme elevations among patients on antiretroviral therapy (ART) were determined by prospectively evaluating aspartate aminotransferase (AST) data in a cohort of patients in Kampala over 36 months. A proportion of patients had hepatitis B virus (HBV) status determined. Hepatotoxicity was graded I to IV according to the AIDS Clinical Trial Group criteria. Of 546 patients, 377 (69%) were women; overall median baseline CD4+ T-cell was 97/μL (interquartile range [IQR] 20-164). Hepatitis B surface antigen (HBsAg) was detected in 42 (9%) of 470 persons. ART included lamivudine, with either nevirapine and d4T (74%) or efavirenz and AZT (26%). Median (IQR) AST level at baseline was 35 (27, 53 IU/L). Over 36 months, only eight patients had grade III AST elevation. Neither HBsAg nor ART regimen influenced AST levels. Male gender and CD4+ change from baseline were correlated with AST elevation. Patients with HIV/HBV co-infection were not at an increased risk of AST elevation, which occurred uncommonly in this setting.