HIV Ag-Ab Research Articles

A-245 Reagent Lot Variation—When should I be Concerned?

Abstract Background Reagent lot variation is often considered a major source of concern for infectious disease serology testing. Regular review of quality control testing data for specific assays confirms that, when using traditional statistical methods, such as using small datasets to establish mean/SD and then applying Westgard rules, reagent lot variation is the most common cause of variation observed. To investigate every incident is time consuming, costly and likely unnecessary in the majority of cases. But how do we create an alternative to monitoring QC data that accepts normal reagent lot variation yet highlight unacceptable variation? Applying the results from two assays using the same multimarker QC sample to traditional and an alternative QC monitoring method such as QConnect highlights when we should be concerned with lot variation and when the variation is normal. Methods QC testing data from 14 lots of the multimarker QC “Optitrol Blue” over a three year period tested on two assays—Abbott ARCHITECT Anti-HCV (n = 54 102) and Abbott ARCHITECT HIV AgAb Combo (n = 62 682) were reviewed for lot variation using traditional and alternative QC monitoring methods. Results Numerous examples of lot variation were identified from the two assays over the three-year period. Applying traditional QC methods resulted in frequent recalculation of mean/SD to accommodate the lot variation, effectively making the lot variation part of the routine, negating its importance, and making the clinical significance of reagent lot variation difficult to ascertain. Using an alternative QC monitoring method such as QConnect, which incorporated normal lot in calculations to create a constant acceptance range, removed the uncertainty and highlighted instances where variation was outside ‘normal’, triggering further investigation by using meaningful QC ranges. A clear example was observed where two similar looking Levey-Jennings charts (one for ARCHITECT HCV and one for ARCHITECT HIV) demonstrated reagent lot variation that was detected as an outlier whereas Traditional methods identified all reagent lots as being outliers. Conclusion In infectious disease serology testing, reagent lot variation is frequent, normal, and rarely a cause for concern. However, it is difficult to determine how much variation is acceptable when using traditional QC methods, because most lot changes are flagged as “rejections”. QC processes that incorporate normal reagent lot variation, derived from historical data, allows for rapid identification of unacceptable variation, saving money and time (particularly when all reagent lot variation identified as outliers need unnecessary investigation), while reducing risk of poor results.

Prospective Laboratory Evaluation of the cobas Plasma Separation Card for HIV and Treponema pallidum Antibody Analysis.

The cobas Plasma Separation Card (PSC; Roche Diagnostics) was developed for HIV viral load testing. This study evaluates the performance of HIV and Treponema pallidum (Tp) antibody (Ab) detection on PSCs as an alternative to dried blood spots (DBSs). EDTA whole blood samples were collected from HIV-positive (n = 100), HIV-negative (n = 50), Tp-positive (n = 100), and Tp-negative patients (n = 50) and spotted on DBS and PSC. Antibody detection performance was evaluated for HIV Ab using the Genscreen ULTRA HIV Ag-Ab test (Bio-Rad) and for Tp Ab using the Syphilis Total Ab test (Bio-Rad). Plasma was used as a reference specimen. Receiver operating characteristic curve analysis for DBS and PSC generated areas under the curve (AUC + 95% confidence interval) of 0.985 (0.960-1.000) and 0.987 (0.973-1.000) for HIV Ab and 1.000 (1.000-1.000) and 0.996 (0.983-1.000) for Tp Ab, respectively. Receiver operating characteristic areas under the curve were not significantly different between DBS and PSC for HIV or TP Ab. At selected cutoff values rendering at least 99% sensitivity for HIV Ab detection, the specificity was 96% on DBS and 68% on PSC. For Tp Ab detection at 90% sensitivity, 100% specificity is reached on both DBS and PSC (exceeding the required 95%). However, the median quantitative HIV and Tp Ab signal of positive samples significantly decreased in PSC compared with DBS and plasma. Although receiver operating characteristic analysis does not seem to indicate significant differences in performance between DBS and PSC, the significant reduction in quantitative Ab detection signal dictates card composition optimization before its use for HIV and Tp Ab detection can be advised.

Increased risk of false-positive HIV ELISA results after COVID-19.

From the first-generation options available in 1985, tests to detect HIV-1 specific antibodies have increased its sensitivity and specificity. HIV-1 and SARS-CoV-2 surface glycoproteins present a certain degree of homology and shared epitope motifs, which results of relevance as both pandemics coexist. Here, we aimed to evaluate the rate of false-positive HIV serology results among individuals with COVID-19 diagnosis and in vaccinated individuals. A retrospective analysis of the samples stored at the Infectious Disease Biobank in Argentina from donors with previous COVID-19 diagnosis or anti-SARS-CoV-2 vaccination. Plasma samples were analyzed using Genscreen Ultra HIV Ag-Ab. In those with a positive result, the following assays were also performed: ELISA lateral flow Determine Early Detect; RecomLine HIV-1 & HIV-2 IgG and Abbott m2000 RealTime PCR for HIV-1 viral load quantification. In all samples, the presence of anti-SARS-CoV-2 IgG antibodies was evaluated by ELISA using the COVIDAR kit. Statistical analysis was done using Pearson's and Fisher's exact chi-squared test; Mann-Whitney and Kruskal-Wallis tests. Globally, the false-positive HIV ELISA rate was 1.3% [95% confidence interval (95% CI) 0.66-2.22; χ2 = 4.68, P = 0.03, when compared with the expected 0.4% false-positive rate]. It increased to 1.4% (95% CI 0.70-2.24, χ2 = 5.16, P = 0.02) when only samples from individuals with previous COVID-19 diagnosis, and to 1.8% (95% CI 0.91-3.06, χ2 = 7.99, P = 0.005) when only individuals with detectable IgG SARS-CoV-2 antibodies were considered. This higher occurrence of HIV false-positive results among individuals with detectable antibodies against Spike SARS-CoV-2 protein should be dispersed among virology testing settings, health providers, and authorities.

Development of quantified HIV-1 antigen panel for evaluating HIV Ag/Ab combination tests using the RT-qPCR method

We established a human immunodeficiency virus type 1 (HIV-1) antigen (Ag) panel from culture supernatants of 27 HIV-1 isolates, including 11 HIV-1 subtypes, circulating recombinant forms (CRFs), and groups (HIV-1 types), to evaluate the HIV-1 Ag detection sensitivity and HIV-1 type specificity of three HIV-1 Ag/antibody (Ab) combination tests approved in Japan. The HIV-1 copy numbers were quantified by the reverse transcription quantitative polymerase chain reaction (RT-qPCR) method. They were diluted to four different copy numbers and used in this evaluation. Enzygnost HIV Integral IV gave HIV-positive results in nearly all samples, with the single exception being an HIV-negative result in a case with a value just below the cut-off in a CRF08_BC member (100,000 copies/mL). Genscreen HIV Ag-Ab ULT showed low sensitivity to HIV-1 group O members, but this is not an urgent problem as no HIV-1 group O infection cases have been reported in Japan. The detection sensitivity of Determine HIV Early Detect was lower than that of the aforementioned two tests by ten-to hundred-fold, indicating that the kit may have limited performance in the acute phase of HIV-1 infection. Our HIV-1 Ag panel is useful for evaluating the HIV-1 Ag sensitivity of HIV-1 Ag/Ab combination tests.

Performance characteristics of two new rapid HIV diagnostic assays and use of test band reader

PurposeAccurate HIV diagnosis is essential for appropriate patient care. This present study evaluated the performance of two different new rapid HIV diagnostic tests; 1) TRUSTline HIV-1/2 Ab rapid test (Athenese-DxPvt. Ltd, Chennai, India)and 2) OnSite HIV 1/2 Ab Plus Combo Rapid Test (CTK Biotech Inc., San Diego, USA) and also validated ALTA Rapid Test Reader (RTR-1) (CTK Biotech Inc., San Diego, USA), the device is a user-friendly and image-analysis based qualitative/semi-quantitative tabletop reader. MethodsA total of n ​= ​500 characterized specimens were used for this evaluation and the results of the new test kits (TRUSTline and OnSite) were also compared with 4th generation ELISA kit (Genescreen™Ultra HIV Ag-Ab ELISA) and 3 other commercially available rapid tests that were in the market; 1)SD Bioline™ HIV 1/2 3.0, 2) Aspen® HIV 1/2 Rapid Ab Test and 3) Diagnostic enterprises HIVTRI-DOT. The test band intensities of the TRUSTline and OnSite tests were measured in an ALTA rapid test reader and compared with the naked eye reading. ResultsThe sensitivity, specificity, positive predictive value, negative predictive value and efficacy of TRUSTline and OnSite were 100%, 99.6%, 99.5%, 100% and 99.8% and 100%, 100%, 100%, 100% and 100% respectively. ConclusionsThe ‘TRUSTline HIV-1/2’ and ‘OnSite HIV 1/2' kits are suitable to use in the HIV testing algorithm. Use of the ALTA rapid test reader could be user's friendly in the field level testing in resource-limited settings”.

Comparative evaluation of ADVIA Centaur® XP chemiluminescence system for screening of HBV, HCV, HIV and syphilis in Indian blood donors

BackgroundThe introduction of chemiluminescent immunoassay (CLIA) in blood donor screening has led to a gradual replacement of enzyme-linked-immunosorbent assay (ELISA) as the former offers automation, higher sensitivity and lower turn-around-time. However, only a few CLIA platforms are used for blood donor screening in India. The present study evaluated one such newer platform viz., Adiva Centaur XP CLIA for screening of HBV, HCV, HIV and syphilis. Material and methodsProspective comparative study wherein 4843 whole blood donors were screened for HBsAg, Anti-HCV, HIV Ag-Ab and Anti-treponemal antibodies in both Advia Centaur XP and Architect i2000SR platforms. Additional tests were performed in samples which were reactive in only one of the platforms. The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, false positive rate and false negative rate of both the platforms were compared. Kappa coefficient was calculated to determine the agreement between the testing platforms. ResultsThe sensitivity of Advia Centaur platform for HBV, HCV, HIV and syphilis detection were 94.9 %, 100 %, 100 % and 100 % respectively as compared to 96.6 %, 100 %, 100 % and 100 % in Architect i2000SR platform. The specificity of both the platforms were 99.8−99.9 % for all the four tests. The agreement between the two platforms was almost perfect for HBV, HCV and syphilis testing; and fair for HIV testing. ConclusionThe Advia Centaur CLIA platform was found to be comparable with the Architect CLIA platform for blood donor screening. Unexpected finding was the occurrence of HBV false negatives in both the platforms, possibly due to HBsAg mutations.

Laboratory-Based Evaluation of SD Bioline HIV/Syphilis Duo Rapid Test Kits in the Gambia, November 2019

Background: HIV and syphilis are mainly diagnosed using separate rapid test kits for the HIV counseling and testing (HCT), Prevention of Mother-to-Child Transmission of HIV (PMTCT) and other clinical requests in healthcare facilities in The Gambia, as recommended in the HIV testing management guidelines. The goal of this study was to evaluate the performance of SD Bioline HIV/ Syphilis Duo as a single test kit used for the simultaneous detection of HIV & Syphilis antibodies in the laboratory setting. Methods: We determined the sensitivity, specificity, positive and negative predictive values of SD Bioline HIV/Syphilis Duo kits in terms of HIV screening against the GenScreen Ultra HIV Ag-Ab ELISA (Lot 9D0126) using a total of 100 HIV negative and 150 HIV positive serum/plasma specimens that were stored at -20°C. Subtyping of the HIV positive specimens was previously performed using First Response HIV-1/2 test cards and Western Blot assays respectively. Moreover, the SD Bioline HIV/Syphilis Duo kit sensitivity, specificity, positive and negative predictive values in relation to Syphilis screening of 100 specimens was also determined against Treponema Pallidum Heamagglutination Assay (TPHA). Results: In terms of HIV screening (n=250), the sensitivity, specificity, positive and negative predictive values of the SD Bioline HIV/Syphilis Duo Test Kits were 100%, 100%, 100%, and 100% respectively when compared with the GenScreen Ultra HIV Ag-Ab ELISA results in the laboratory setting. Sensitivity for Syphilis screening (n=100) was 95.65%, whilst specificity was 100% when compared with TPHA. Positive predictive value was 100%, whilst the negative predictive value was 98.86%. Conclusions: These findings show that the SD Bioline HIV/Syphilis Duo kits have high sensitivity and specificity when used for the detection of HIV and Syphilis antibodies using human serum and/or plasma. Therefore, these kits could serve as a good alternative for the dual elimination of mother-to-child transmission (e-MTCT) HIV and Syphilis through a one-step timely diagnostic procedure, which is crucial in reducing the turnaround time of laboratory test results.

A CASE OF CHRONIC PULMONARY ASPERGILLOSIS AS THE INITIAL PRESENTATION FOR SARCOIDOSIS

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Subacute invasive pulmonary aspergillosis is a locally invasive subacute form of chronic pulmonary aspergillosis (CPA) which typically involves the upper lobes of individuals with pre-existing lung disease or immunodeficiency. Patients with chronic fibrocystic sarcoidosis are prone to CPA. We described a case of sarcoidosis complicated with CPA which was diagnosed concomitantly. CASE PRESENTATION: A 34 year old male with no past medical history presented with hemoptysis for 3 days, associated with chronic productive cough, exertional dyspnea and skin rashes over his arms and face for the past year. Physical examination revealed multiple violaceous plaque over bilateral upper arms and face; reduced breath sounds over bilateral upper zones. CT Chest revealed bilateral upper lobes cavitations, left upper lobe mass-like consolidation, approximately 2.9 cm with air crescent sign. Laboratory tests were notable for lymphopenia, ESR 43 mm/h, CD4+ count 244, Aspergillus Ag 0.6, Aspergillus IgG positive, serum ACE 178 U/L, fungal culture from bronchial alveolar lavage (BAL) isolated Aspergillus species. ANCA, Histoplasma Ag, Cryptococcal Ag, HIV Ag-Ab, Quantiferon TB, Sputum acid fast smear were negative. Endobronchial ultrasound with fine needle aspiration (FNA) of subcarinal lymph nodes showed non-caseating granuloma. Skin biopsies of upper extremities skin lesions showed non-caseating granulomas without microorganisms seen. The patient was started on Voriconazole for 3 months duration and scheduled for outpatient follow up. DISCUSSION: Patients with sarcoidosis are predisposed to CPA due to underlying pulmonary involvement especially with fibrocystic sarcoidosis in addition to the mildly immunocompromised state, as evidenced by low CD4 count. The diagnosis of CPA was made based on symptomatology (chronic productive cough, dyspnea and hemoptysis), bilateral upper lobe cavitations on CT Chest, positive Aspergillus IgG and positive BAL culture for Aspergillus species. It was a challenge in making concomitant diagnosis of Sarcoidosis as it is a diagnosis of exclusion. Diagnosis of sarcoidosis cannot be made based on the non-caseating granulomas resulted from the FNA of the lymph nodes as aspergillosis can present with similar picture. The skin rash which appeared to be plaque sarcoidosis ultimately leads us to the diagnosis of sarcoidosis after confirmation of non-caseating granuloma on skin biopsy. CONCLUSIONS: Patients with CPA typically present with background risk factors of underlying lung disease. It is essential to have a high clinical suspicion for underlying undiagnosed disease processes especially when individuals presented with CPA without any obvious risk factors. CPA is a serious complication of sarcoidosis and is associated with high mortality and morbidity. Unfortunately, there is no consensus currently on how to best treat patients diagnosed with sarcoidosis and CPA. REFERENCE #1: Denning DW, Cadranel J, Beigelman-Aubry C, et al. Chronic pulmonary aspergillosis: rationale and clinical guidelines for diagnosis and management. Eur Respir J. 2016;47(1):45-68. doi:10.1183/13993003.00583-2015 REFERENCE #2: Alastruey-Izquierdo A, Cadranel J, Flick H, et al. Treatment of Chronic Pulmonary Aspergillosis: Current Standards and Future Perspectives. Respiration. 2018;96(2):159-170. doi:10.1159/000489474 REFERENCE #3: Denning DW, Pleuvry A, Cole DC. Global burden of chronic pulmonary aspergillosis complicating sarcoidosis. Eur Respir J. 2013;41(3):621-626. doi:10.1183/09031936.00226911 DISCLOSURES: No relevant relationships by Farahnaz Anwar, source=Web Response No relevant relationships by James Choi, source=Web Response No relevant relationships by Si Yuan Khor, source=Web Response No relevant relationships by Jason Liu Liu, source=Web Response No relevant relationships by Akhil Sharma, source=Web Response No relevant relationships by Enhua Wang, source=Web Response

Laboratory-based Evaluation of Wondfo HIV1/2 Rapid Test Kits in the Gambia, December 2020

Background: HIV rapid diagnosis in The Gambia is mainly done using Determine HIV-1/2 and First Response HIV 1.2.0 or SD Bioline HIV-1/2 3.0 for screening and sero-typing of HIV respectively among children and adults. Polymerase Chain Reaction (PCR) is used for the detection of the HIV viral genome among infants born to HIV positive mothers. This is the HIV testing Algorithm recommended in the HIV testing guidelines of The Gambia for both HIV Counseling and Testing (HCT), Prevention of Mother-to-Child Transmission of HIV (PMTCT) as well as other clinical requests for HIV testing. At the National Public Health Reference Laboratories (NPHRL), ELISA is the first line of testing for HIV while First Response HIV 1.2.0 or SD Bioline HIV 1/2 3.0 is used for preliminary serotyping. MP Diagnostics HIV Blot 2.2 Western Assay, which is the gold standard for HIV testing in The Gambia, is used as the tie breaker (i.e., when there are discordant results). The aim of this study was to evaluate the sensitivity and specificity of the Wondfo HIV 1/2 rapid test kit for the detection of human antibodies to HIV in serum/plasma/whole blood and dried blood spots. Methods: The sensitivity, specificity, positive and negative predictive values of Wondfo HIV 1/2 kits were evaluated in terms of HIV screening against Determine HIV1/2, GenScreen Ultra HIV Ag-Ab ELISA and First Response HIV 1.2.0 using a total of 401 samples. Of these, 351 were sera/plasma samples {100 HIV negative, 250 HIV positive and 1 indeterminate that were stored at -20°C, 26 were whole blood samples (4 negative, 22 positive), and 24 were dried blood spot (DBS) specimens (16 negative and 8 positive) were used for this evaluation. HIV positive specimens were previously sero-typed using First Response HIV-1.2.0 test cards and MP Diagnostics HIV Blot 2.2 Western Assay. Results: The evaluation shows that the sensitivity, specificity, positive and negative predictive values of Wondfo HIV 1/2 Test Kits with regards to HIV Screening when compared with the GenScreen Ultra HIV Ag-Ab ELISA and First Response 1.2.O (n=401) were 100%, 100%, 100%, and 100% respectively. Similarly, the sensitivity, specificity, positive and negative predictive values of Wondfo HIV 1/2 Test Kits with regards to HIV Screening compared to Determine HIV1/2 (n=401) were 99.64%, 100%, 100%, and 99.17% respectively. Conclusions: This study demonstrates that Wondfo HIV 1/2 test kits have a high sensitivity and specificity when used for the detection of HIV antibodies using human serum/plasma, whole blood or DBS.

The Most Common Causes of Transfusion-Transmitted Diseases among Blood Donors in the Middle Eastern States

The need for blood is essential, but there is no timely access to safe blood for millions of individuals who need a transfusion. Additionally, blood transfusions can also be the fastest and simplest form of checking for the existence of transfusion-transmitted diseases to the recipients. Blood safety concerns are an issue of great concern in Middle Eastern Countries in which the inaccessibility or provision of unsafe blood has an adverse effect on morbidity and mortality in the region. Additionally, many organizations and safety procedures of blood transfusion in this region need to be updated. Articles containing the key phrases Middle Eastern Countries, Blood, blood donor, blood transfusion, transfusion safety, transfusion-transmitted infections, and transfusion guidelines published from 2003 to 2020 in MEDLINE, PubMed, Scopus, and Google Scholar. Therefore, to determine the most prevalent causes of transfusion-transmitted disease among blood donors in the Middle East countries, this literature review was intended for research.
 Based on the data gathered were potentially related to HBsAg and HCV prevalence in blood donors from most of the middle eastern countries. While no positive cases of either HIV Ag-Ab or syphilis antibodies have been recorded especially among the blood donated from Egypt and Saudi Arabia. Based on recent studies findings, WHO, and the Food and Drug administration transfusion transmission of SARS-CoV-2 to recipients did not occur via blood transfusion. So that, In Middle Eastern countries, transfusion-transmitted infection remains a formidable problem. A similarly wide constellation of economic and operational challenges in the area parallels the diverse array of pathogens; this calls for a systemic solution that, as proposed by the WHO, involves regulatory, structural, and training initiatives.

Detection of HIV-1 and -2 Antibodies among Children and Knowledge, Attitude, Perceptions and Practices (KAPP) of Their Parents in Port Harcourt, Nigeria

Aim: Paediatric testing for HIV in low-income and middle-income countries is poor and must be raved up as this is important for treatment and survival among this disease-prone demographic area. This study was carried out to detect the presence of HIV-1 and -2 antibodies among children receiving health care service in the University of Port Harcourt Teaching Hospital (UPTH), Port Harcourt, Rivers State, Nigeria. It also aimed to assess the knowledge, attitude, perceptions and practices of their parents on HIV/AIDS in Port Harcourt, Nigeria.
 Study Design: Cross-sectional study.
 Place and Duration of Study: University of Port Harcourt Teaching Hospital (UPTH) in Port Harcourt, Nigeria, between August 2012 and July 2015.
 Methods: One hundred subjects (58 males and 42 females) were used in this study. Blood samples were collected randomly from children in the outpatient department of the hospital. HIV-1/2 was detected using Gen ScreenTM ULTRA HIV Ag-Ab Kit (BIO-RAD), an ELISA based test kit following the manufacturer's instructions.
 Results: The overall prevalence was found to be 5.0%. The gender-specific infection rate shows that males had a higher infection rate (5.2%) for HIV infection than their female counterparts (4.8%). The age-specific prevalence showed that the children in age groups 8-10 years had a higher prevalence (6.7%) than those 2-4 years (4.5%) and 5-7 years (4.2%). None appeared to be significantly associated (P>0.05) with HIV-1/2 antibodies prevalence among the children population. The knowledge, attitude, perceptions and practices of parents of the children indicate that 100.0% of them believed HIV/AIDS is real and children live with it; 62.0% have been screened for HIV before while 38.0% have not; 77.0% believe HIV cannot be cured while 19.0% believe it can; 66.0% know that it can be transmitted from mother to child whereas 16.0% believe it cannot and 70.0% confirmed they share sharp objects.
 Conclusion: This study however further confirmed the presence of HIV-1 and 2 antibodies among Children in Port Harcourt, Nigeria. HIV can affect all age groups, both males and females. Health education campaigns and training on HIV prevention and control is recommended.

Data on the relationship of signal-to-cutoff ratio of two HIV antigen/antibody combination assays to subsequent confirmation of HIV-1 infection in a low-prevalence population.

HIV-1/2 antigen/antibody (Ag/Ab) immunoassays that detect HIV-1 and HIV-2 antibodies and HIV-1 p24 antigen are commonly used in the diagnosis of HIV-1/HIV-2 infections in human plasma/serum. Samples from patients with positive screening results require confirmation by antibody differentiation and/or HIV PCR assays. HIV screening assays are commonly reported as positive or negative based on a signal-to-cutoff (S/CO) threshold. For some HIV screening assays, the strength of the S/CO value correlates with likelihood that confirmatory testing will be positive. The data in this article provide results from two HIV Ag/Ab combination assays (Abbott Architect HIV Ag/Ab Combo Assay, a 4th generation combination assay; Bio-Rad Bioplex 2200 HIV Ag-Ab Assay, a 5th generation assay). The data include 23,331 HIV screening results, S/CO ratios, antibody differentiation or Western blot results (for samples with positive HIV screens), HIV-1 PCR results (if performed), patient location at time of testing, age, and sex. Distribution of S/CO ratios for the Bio-Rad HIV screening assay data and the distribution of S/CO values for samples with positive screening results were analyzed.

Could HIV-1 RNA Testing be an Option as the Second Step in the HIV Diagnostic Algorithm?

There is benefit to early HIV-1 diagnosis and treatment, but there is no Food and Drug Administration-approved quantitative assay with a diagnostic claim. We compared the performance of the Hologic Aptima HIV-1 Quant (APT-Quant) and Aptima HIV-1 Qual (APT-Qual) assays for diagnostic use and the performance of a diagnostic algorithm consisting of Bio-Rad BioPlex 2200 HIV Ag-Ab assay (BPC) followed by APT-Quant (2-test) compared with BPC followed by Geenius HIV-1/2 supplemental assay (Geenius) with reflex to APT-Qual (3-test). Five hundred twenty-four plasma, which included 419 longitudinal specimens from HIV-1 seroconverters (78 were after initiating antiretroviral therapy [ART]) and 105 from ART-naive persons with established HIV-1 infections, were used to evaluate APT-Quant performance for diagnostic use. Specimens from 200 HIV-negative persons were used to measure specificity. For the algorithm comparison, BPC-reactive specimens were evaluated with the 2-test or 3-test algorithm. McNemar's test was used to compare performance. The APT-Quant detected more samples early in infection compared with APT-Qual. The APT-Quant specificity was 99.8%. Before ART initiation, the algorithms performed similarly among samples from different stages of infection. After ART initiation, the 3-test algorithm performed significantly better (P = 0.0233). The APT-Quant has excellent performance for diagnostic use. The 2-test algorithm works well in ART-naive samples, but its performance decreases after the IgG response is elicited and with ART-induced suppressed viremia. Providing confirmation and viral load assay with 1 test result could be advantageous for patient care. However, additional factors and challenges associated with the implementation of this 2-test algorithm, such as cost, specimen type, and collection need further evaluation.

COMPARATIVE EVALUATION OF THE 4TH GENERATION ELISA/CLIA ASSAYS USED FOR THE DIAGNOSIS OF HIV INFECTION IN THE RUSSIAN FEDERATION

The aim of the work was to compare the five most widely used ELISA diagnostic kits on the territory of the Russian Federation, which are used for screening for HIV infection.Materials and methods. 5442 samples from visitors of diagnostic centers who came for blood donation for non-infectious analyses, cohorts with a high risk of HIV infection, as well as patients with potentially interfering conditions were used as a material for the study. Additionally, seroconversion panels and a panel of viral diversity were used to evaluate the analytical characteristics. The following test systems were compared: Architect HIV Ag/Ab Combo (Abbott), Genscreen Ultra HIV Ag-Ab (Bio-Rad), CombiBest HIV-1,2 AG/AT (Vector-Best), DS-ELISA-HIVAGAT-SCREEN (Diagnostic Systems), HIV-1,2-AG/AT (Medical-Biological Union).Conclusion. The diagnostic sensitivity of all tests was 100% with the exception of one (Medical-Biological Union), in which it turned out to be 99,54%. Diagnostic specificity ranged from 99,58% to 99,89%, but unexpectedly strongly depended on the test population, decreasing on a group with a high risk of HIV infection to 93,26% (Vector-Best). The convergence between initial and repeat reactive samples ranged from 100% (Abbott) to 89,51% (Vector-Best). The results of the analysis of seroconversion panels showed that the tests differed slightly from each other, receiving positive results from 22,12% (Diagnostic Systems) to 27,88% (Abbott) samples. When testing the panel of viral diversity, diagnostic tests from foreign manufacturers showed better results, revealing 100% (Abbott) and 85,9% (Bio-Rad). The smallest number of panel samples was detected by the kit of the Medical-Biological Union (52,1%). This work is the only study where the 4th generation ELISA kits, widely used in the Russian Federation for screening for HIV infection, were compared in an extensive sampling. The results obtained make it possible to evaluate the effectiveness of the use of the listed kits in routine diagnostic practice.

Role of Nucleic Acid Test (NAT) in Detection of Transfusion Transmitted Viruses in Comparison to Other Methods

Background: over the two last decades, much attention has been given to the prevention of transfusion-transmitted viral infections. Given the potential transmission of viruses during the window period, novel non-serology based approaches such as viral nucleic acid testing (NAT) have been established. Objective: a comparative study of different methods to detect transfusion transmitted viral infections. Materials and methods: this cross-sectional study was conducted at the Egyptian National Blood Transfusion Center (NBTC), Giza. The duration of the research was 2 months from June 2018 to august 2018. In our study 1000 donor samples were tested by ELISA and NAT tests for HBV, HCV and HIV. Results: regarding ELISA tests of the three viruses, only 14 (1.4%) samples were finally HBsAg reactive. Finally, reactive HCVAb were 22 (2.2%) samples, while only 4 (0.4%) samples were HIV Ag-Ab finally reactive. We found highly statistical significant difference between initial and final results of ELISA (p<0.001). Regarding NAT testing of the three viruses. HBV: 5 (0.5%) samples were NAT and ELISA reactive, 1 was NAT yield. HCV: 9 (0.9%) samples were NAT and ELISA reactive. HIV one sample (0.1%) was NAT and ELISA reactive, one (0.1%) was NAT yield. Statistical significant difference was found in comparison between NAT and ELISA in HBV, HCV, and HIV p values <0.001, <0.001, and = 0,008 respectively. Conclusion: we concluded that NAT and ELISA are complementary to each other. NAT is an effective method for safeguarding the blood supply.

BioRad BioPlex® HIV Ag-Ab assay: Incidence of false positivity in a low-prevalence population and its effects on the current HIV testing algorithm

BackgroundThe BioPlex® HIV Ag-Ab assay, unlike other HIV 1/2 antigen/antibody immunoassays, is capable of differentiating positive HIV-1 antibodies (Groups M and O) from HIV-2 antibodies and/or HIV-1 p24 antigen in a single test. ObjectiveThe Alaska State Virology Laboratory (ASVL) adopted the BioPlex® HIV Ag-Ab assay early 2017 and can report on its performance in terms of false positivity in a low-prevalence population and its effects on the current HIV testing algorithm recommended by the Centers for Disease Control and Prevention (CDC). Study DesignSpecimens received between March 2017 and August 2018 were screened using the BioPlex® HIV Ag-Ab assay. Specimens screening positive for HIV antibodies or antigen were further confirmed using the Geenius™ HIV 1/2 Supplemental Assay and/or HIV RNA testing. ResultsOf the 12,338 sera screened by the BioPlex assay for HIV, 35 specimens were positive. Only 22 of the specimens were confirmed by supplemental testing and were considered to be truly positive (PPV, 62.9%). RNA was not detected in these cases suggesting initial false positivity on the BioPlex® HIV Ag-Ab assay. True positive results had index values (IDX) of >180 whereas false positive IDX’s were between 1 and 4, with the exception of one specimen. ConclusionsWe suggest that specimens demonstrating positivity with low IDX values <4 on the BioPlex® HIV Ag-Ab assay proceed directly to RNA testing, essentially bypassing supplemental antibody confirmation tests, to reduce turnaround time and cost of HIV confirmation.

Prevalence of HIV in a Cohort of Pregnant Women Attending a Tertiary Hospital in Ibadan, Nigeria

HIV/AIDS is one of the major barriers to community development. It is a global pandemic with high prevalence rates worldwide. This research was carried out to determine the prevalence of HIV among pregnant women attending the antenatal clinic at the University College Hospital, Ibadan using Enzyme Linked Immunosorbent Assay (ELISA) Gen Screen TM ULTRA HIV Ag-Ab Kit. HIV prevalence was found to be 26.4%. A total of 91 samples were tested, 24 (26.4%) were found to be positive and 67 (73.6%) negative. Women between the ages 25 – 31 had the highest prevalence rate of 16.5% while those between the ages of 39 – 45 years had the least prevalence rate of 1.1%. The results revealed a relatively high prevalence rate for HIV among pregnant women which suggests the need for active surveillance and implementation of preventive measures to avoid further spread of the virus. Pregnant women need to be continually tested for HIV and those infected monitored closely to prevent mother to child transmission.

Transfusion-Transmissible Infections: Seroprevalence among Donors in an Egyptian University Blood Bank

Background: Blood safety is facing a major challenge in Egypt, having a high recorded prevalence of Hepatitis C virus antibodies (HCV Ab). Egypt is facing a new era after three years of starting the implementation of the new antivirals for HCV infected individuals and 25 years of the compulsory vaccination program of hepatitis B. Aim: to estimate the seroprevalence of Hepatitis B and C viruses, HIV, and Trepenoma Pallidum antibodies among blood donors in a university blood bank. Materials and Methods: A retrospective study was conducted at Suez Canal University blood bank based on official records. 53138 donors’ data were analyzed from Jan 2015 to July 2018. Results: Among blood donors the prevalence of HCV Ab and HBsAg was 1.87 % and 0.97% respectively. No recorded positive cases of either HIV Ag-Ab or syphilis antibodies among the donated blood in this period. Percentages of positive HBsAg among family replacement donors (RD) and volunteer donors (VD) were decreased from 1.1% and 1.17 % in 2015 to 0.91% and 0.96% in 2018. Moreover, seropositivity for HCV Ab was declined in both RD and VD from 3% and 2.5% in 2015 to 1.3% and 1.4% in 2018, respectively. Conclusion: The prevalence of HCV and HBV is decreasing among blood donors and this may be attributed to the increasing awareness regarding blood-transmitted, hepatitis B vaccination, adherence to strict donation criteria, and introduction of oral direct acting antivirals.

Diagnostic accuracy of HIV test kits, Genscreen Ultra and Bioelisa.

PurposeGenetic diversities in different countries affect the performance of HIV test kits. Therefore, WHO recommends evaluation of every HIV test kit in countries’ context before its use. Therefore, this study aimed to evaluate the performance of Genscreen ULTRA HIV Ag–Ab and Bioelisa.Materials and methodsThe study had used 400 characterized plasma samples obtained from CDC Atlanta bio-bank derived from Africa, USA, and Thailand.ResultsDiagnostic performance of both test kits under evaluation was assessed at 95% CI. Genscreen ULTRA HIV Ag–Ab had sensitivity and negative predictive value of 99.5% [95% CI, 97.2–99.9] and the specificity and positive predictive value of 98.5% [95% CI, 95.7–99.7]. Bioelisa HIV test kit had exhibited sensitivity and negative predictive value of 99% [95% CI, 96.4–99.7] and specificity and positive predictive value of 98.5% [95% CI, 95.7–99.7]. Both test kits were able to detect almost all samples with HIV-2, dual infections, and seroconversion.ConclusionBoth the test kits were highly sensitive and specific in detecting HIV. However, there are still few samples containing HIV antibody which were not identified by both kits. Therefore, additional screening measures should be done in using these assays for blood transfusion and organ transplantation. In addition, the study can be used as a reference by other African countries.

Performance of the BioPlex 2200 HIV Ag-Ab assay for identifying acute HIV infection

BackgroundAssays that detect HIV antigen (Ag) and antibody (Ab) can be used to screen for HIV infection. ObjectivesTo compare the performance of the BioPlex 2200 HIV Ag-Ab assay and two other Ag/Ab combination assays for detection of acute HIV infection. Study designSamples were obtained from 24 individuals (18 from the US, 6 from South Africa); these individuals were classified as having acute infection based on the following criteria: positive qualitative RNA assay; two negative rapid tests; negative discriminatory test. The samples were tested with the BioPlex assay, the ARCHITECT HIV Ag/Ab Combo test, the Bio-Rad GS HIV Combo Ag-Ab EIA test, and a viral load assay. ResultsTwelve (50.0%) of 24 samples had RNA detected only ( > 40 to 13,476 copies/mL). Ten (43.5%) samples had reactive results with all three Ag/Ab assays, one sample was reactive with the ARCHITECT and Bio-Rad assays, and one sample was reactive with the Bio-Rad and BioPlex assays. The 11 samples that were reactive with the BioPlex assay had viral loads from 83,010 to >750,000 copies/mL; 9/11 samples were classified as Ag positive/Ab negative by the BioPlex assay. ConclusionsDetection of acute HIV infection was similar for the BioPlex assay and two other Ag/Ab assays. All three tests were less sensitive than a qualitative RNA assay and only detected HIV Ag when the viral load was high. The BioPlex assay detected acute infection in about half of the cases, and identified most of those infections as Ag positive/Ab negative.