Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-11 (of 11 Records) |
Query Trace: Ou CY[original query] |
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Past, present and future molecular diagnosis and characterization of human immunodeficiency virus infections.
Tang YW , Ou CY . Emerg Microbes Infect 2012 1 (8) e19 Substantive and significant advances have been made in the last two decades in the characterization of human immunodeficiency virus (HIV) infections using molecular techniques. These advances include the use of real-time measurements, isothermal amplification, the inclusion of internal quality assurance protocols, device miniaturization and the automation of specimen processing. The result has been a significant increase in the availability of results to a high level of accuracy and quality. Molecular assays are currently widely used for diagnostics, antiretroviral monitoring and drug resistance characterization in developed countries. Simple and cost-effective point-of-care versions are also being vigorously developed with the eventual goal of providing timely healthcare services to patients residing in remote areas and those in resource-constrained countries. In this review, we discuss the evolution of these molecular technologies, not only in the context of the virus, but also in the context of tests focused on human genomics and transcriptomics. |
Diagnosis of human immunodeficiency virus infection
Parekh BS , Ou CY , Fonjungo PN , Kalou MB , Rottinghaus E , Puren A , Alexander H , Hurlston Cox M , Nkengasong JN . Clin Microbiol Rev 2019 32 (1) HIV diagnostics have played a central role in the remarkable progress in identifying, staging, initiating, and monitoring infected individuals on life-saving antiretroviral therapy. They are also useful in surveillance and outbreak responses, allowing for assessment of disease burden and identification of vulnerable populations and transmission "hot spots," thus enabling planning, appropriate interventions, and allocation of appropriate funding. HIV diagnostics are critical in achieving epidemic control and require a hybrid of conventional laboratory-based diagnostic tests and new technologies, including point-of-care (POC) testing, to expand coverage, increase access, and positively impact patient management. In this review, we provide (i) a historical perspective on the evolution of HIV diagnostics (serologic and molecular) and their interplay with WHO normative guidelines, (ii) a description of the role of conventional and POC testing within the tiered laboratory diagnostic network, (iii) information on the evaluations and selection of appropriate diagnostics, (iv) a description of the quality management systems needed to ensure reliability of testing, and (v) strategies to increase access while reducing the time to return results to patients. Maintaining the central role of HIV diagnostics in programs requires periodic monitoring and optimization with quality assurance in order to inform adjustments or alignment to achieve epidemic control. |
Evaluation of PIMA point-of-care CD4 analyzer in Yunnan, China
Liang J , Duan S , Ma YL , Wang JB , Su YZ , Zhang H , Ou CY , Hao L , Qi MS , Bulterys M , Westerman L , Jiang Y , Xiao Y . Chin Med J (Engl) 2015 128 (7) 890-5 BACKGROUND: CD4 count is used to determine antiretroviral therapy (ART) eligibility. In China, flow cytometers are mostly located in urban areas with limited access by patients residing in remote areas. In an attempt to address this issue, we conducted a study to validate the performance of Alere PIMA point-of-care CD4 analyzer. METHODS: Venous and finger-prick blood specimens were collected from HIV-positive participants from two voluntary counseling and testing sites in Yunnan Province. Both venous and finger-prick blood specimens were tested with the PIMA analyzer. Venous blood specimens tested with the Becton Dickinson FACSCalibur were used as a reference. RESULTS: Venous specimens from 396 and finger-prick specimens from 387 persons were available for analysis. CD4 counts by PIMA correlated well with those from FACSCalibur with an R2 of 0.91 for venous blood and 0.81 for finger-prick blood. Compared to FACSCalibur, the PIMA analyzer yielded lower counts with a mean bias of - 47.0 cells/mul (limit of agreement, [LOA]: -204-110 cells/mul) for venous blood and -71.0 cells/mul (LOA: -295-153 cells/mul) for finger-prick blood. For a CD4 threshold of 350 cells/mul, the positive predictive value (PPV) of PIMA was 84.2% and 75.7% and the negative predictive value (NPV) was 97.6% and 95.8% for venous and finger-prick blood, respectively. For an ART threshold of 500 cells/mul, the corresponding PPV was 90.3% and 84.0% and NPV was 94.3% and 93.4%, respectively. CONCLUSIONS: CD4 counting using venous blood with PIMA analyzers is a feasible alternative to a large flow cytometer to determine ART eligibility. |
Impact of proficiency testing program for laboratories conducting early infant diagnosis of HIV-1 in low to middle-income countries
Garcia A , Subbarao S , Zhang G , Parsons L , Nkengasong J , Ou CY , Ellenberger D . J Clin Microbiol 2013 52 (3) 773-80 A voluntary, cost-free external quality assessment (EQA) program established by the U.S. Centers for Disease Control and Prevention (CDC) was implemented to primarily monitor the performance of laboratories conducting HIV Early Infant Diagnosis (EID) from dried blood spots (DBS) in low to middle-income countries since 2006. Ten blinded DBS proficiency test (PT) specimens and 100 known HIV-positive and negative DBS specimens (to be used as internal controls) were shipped tri-annually to participating laboratories with reports for the PT specimens due within 30 days. The participant's results and summary of the performance of all participating laboratories and each diagnostic method were provided after each test cycle. Enrollment in the CDC PT program expanded progressively from 17 laboratories from 11 countries in 2006 to include 136 laboratories from 41 countries at the end of 2012. Despite external pressures to test and treat more children while expanding EID programs, mean PT test scores significantly improved over time as demonstrated by the upward trend from mid-2006 to end of 2012 (P = 0.001) and increase in the percentage of laboratories scoring 100% (P =0.003). The mean test scores plateaued over the past 10 testing cycles, ranging between 98.2 and 99.7% and discordant test results still occur, but at a rate no higher than 2.6%. Analysis of these test results suggests a positive impact of proficiency testing on the testing performance of the participating laboratories and a continuous training program and proficiency testing participation may translate into laboratories improving their testing accuracy. |
Early diagnosis of HIV infection in the breastfed infant
Ou CY , Fiscus S , Ellenberger D , Parekh B , Korhonen C , Nkengasong J , Bulterys M . Adv Exp Med Biol 2012 743 51-65 More than 90% of the 370,000 pediatric human immunodeficiency virus type 1 (HIV-1) infections globally in 2009 were acquired through mother-to-child transmission (MTCT) [1], and most of these transmissions occurred in sub-Saharan Africa. MTCT of HIV-1 occurs either during late pregnancy, the intrapartum period, or breastfeeding [2, 3]. With the application of prophylactic antiretroviral (ARV) therapy and breastfeeding avoidance, MTCT is now observed in only 1–2% of at-risk infants in developed countries [4, 5]. The majority of pregnant women residing in high HIV-burden, resource-limited countries (RLCs) are still not aware of their infection status and do not receive timely intervention measures to prevent vertical transmission [6–11]. Untreated infected infants have high HIV-related morbidity and mortality. Approximately 33% of the untreated infected infants in RLCs die during their first year of life, and >50% die within their first 2 years [12]. Treating infants early greatly reduces mortality and morbidity [13]. Recognition of the importance of reducing infant HIV mortality has facilitated the development of methods to bring appropriate testing closer to pregnant and lactating mothers, to identify HIV-infected infants earlier, and to provide timely access to life-saving ARV treatment and care. New and accurate diagnostic methods have emerged in the last few years, and many of these methods have been field-validated. This diagnostic service should not comprise a stand-alone program but must be integrated into the overall mother and child health programs to achieve the goal of prevention of mother-to-child transmission (PMTCT) [14, 15]. In this chapter, we review currently available diagnostic methodologies, including their advantages and disadvantages, their testing algorithms, and their quality assurance requirements, with a particular focus on early HIV diagnosis in the breastfed infant. Further, we discuss efforts toward the development of simple, accurate, and rapid diagnostic applications. |
Comparison of HIV-1 detection in plasma specimens and dried blood spots using the Roche COBAS Ampliscreen HIV-1 test in Kisumu, Kenya
Okonji JA , Basavaraju SV , Mwangi J , Shiraishi RW , Odera M , Ouma K , Pitman JP , Marum LH , Ou CY , Zeh C . J Virol Methods 2012 179 (1) 21-5 The World Health Organization recommends screening donor blood for HIV in centralized laboratories. This recommendation contributes to quality, but presents specimen transport challenges for resource-limited settings which may be relieved by using dried blood spots (DBS). In sub-Saharan Africa, most countries screen donor blood with serologic assays only. Interest in window period reduction has led blood services to consider adding HIV nucleic acid testing (NAT). The U.S. Food and Drug Administration (FDA) mandates that HIV-1 NAT blood screening assays have a 95% detection limit at or below 100copies/ml and 5000copies/ml for pooled and individual donations, respectively. The Roche COBAS Ampliscreen HIV-1 test, version 1.5, used for screening whole blood or components for transfusion, has not been tested with DBS. We compared COBAS Ampliscreen HIV-1 RNA detection limits in DBS and plasma. An AIDS Clinical Trials Group, Viral Quality Assurance laboratory HIV-1 standard with a known viral load was used to create paired plasma and DBS standard nine member dilution series. Each was tested in 24 replicates with the COBAS Ampliscreen. A probit analysis was conducted to calculate 95% detection limits for plasma and DBS, which were 23.8copies/ml (95% CI 15.1-51.0) for plasma and 106.7copies/ml (95% CI 73.8-207.9) for DBS. The COBAS Ampliscreen detection threshold with DBS suggests acceptability for individual donations, but optimization may be required for pooled specimens. |
Quality assurance in the HIV/AIDS laboratory network of China
Jiang Y , Qiu M , Zhang G , Xing W , Xiao Y , Pan P , Yao J , Ou CY , Su X . Int J Epidemiol 2010 39 Suppl 2 ii72-8 BACKGROUND: In 2009, there were 8273 local screening laboratories, 254 confirmatory laboratories, 35 provincial confirmatory central laboratories and 1 National AIDS Reference Laboratory (NARL) in China. These laboratories were located in Center for Disease Control and Prevention (CDC) facilities, hospitals, blood donation clinics, maternal and child health (MCH) hospitals and border health quarantine health-care facilities. METHODS: The NARL and provincial laboratories provide quality assurance through technical, bio-safety and managerial training; periodic proficiency testing; on-site supervisory inspections; and commercial serologic kit evaluations. RESULTS: From 2002 to 2009, more than 220 million HIV antibody tests were performed at screening laboratories, and all reactive and indeterminate samples were confirmed at confirmatory laboratories. The use of highly technically complex tests, including CD4 cell enumeration, viral load, dried blood spot (DBS)-based early infant diagnosis (EID), drug resistance (DR) genotyping, HIV-1 subtyping and incidence assays, have increased in recent years and their performance quality is closely monitored. CONCLUSION: China has made significant progress in establishing a well-coordinated HIV laboratory network and QA systems. However, the coverage and intensity of HIV testing and quality assurance programmes need to be strengthened so as to ensure that more infected persons are diagnosed and that they receive timely prevention and treatment services. |
Scaling up HIV rapid testing in developing countries: comprehensive approach for implementing quality assurance
Parekh BS , Kalou MB , Alemnji G , Ou CY , Gershy-Damet GM , Nkengasong JN . Am J Clin Pathol 2010 134 (4) 573-84 In the last few years, the use of HIV rapid testing has expanded worldwide in response to the call for universal access to prevention, care, and treatment by UNAIDS and the World Health Organization. HIV rapid testing is performed by people with varied skills in laboratory and nonlaboratory settings. Accurate HIV diagnostic testing is the first step to identifying infected persons for follow-up referral and care. However, there are several challenges related to test kit quality, test selection, testing algorithms, training, quality assurance (QA), quality of new lots, and postmarket performance. We highlight various issues that impact the quality of HIV rapid testing and provide solutions to monitor and improve test accuracy, especially in resource-limited settings. These include the use of validated kits, training with emphasis on QA, use of a standardized log book, dried-tube specimen-based proficiency testing, new kit lot verification, and postmarket surveillance. Systematic implementation of these tools should greatly enhance the quality of HIV rapid testing. |
Detection of low levels of human immunodeficiency virus (HIV) may be critical for early diagnosis of pediatric HIV infection by use of dried blood spots
Walter J , Kuhn L , Semrau K , Decker DW , Sinkala M , Kankasa C , Thea DM , Bulterys M , Ou CY , Aldrovandi GM . J Clin Microbiol 2009 47 (9) 2989-91 We compared a DNA-based assay with a total nucleic acid-based assay for early detection of infant human immunodeficiency virus (HIV) infection. The codetection of DNA and RNA did not result in an overall higher sensitivity compared to that of DNA alone. Discordant results were associated with low levels of HIV DNA, indicating that the sample amount may be critical. |
Dried tube specimens: a simple and cost-effective method for preparation of HIV proficiency testing panels and quality control materials for use in resource-limited settings
Parekh BS , Anyanwu J , Patel H , Downer M , Kalou M , Gichimu C , Keipkerich BS , Clement N , Omondi M , Mayer O , Ou CY , Nkengasong JN . J Virol Methods 2009 163 (2) 295-300 HIV testing has rapidly expanded worldwide, but proficiency testing (PT) programs to monitor and improve the quality of testing are often lacking in resource-limited settings (RLS). Traditional PT programs and quality control reagents use serum/plasma specimens requiring stringent conditions for storage and transportation. A novel, simple and easy to use approach, based on dried tube specimens (DTS), was developed that can help monitor the quality of HIV antibody testing in RLS. DTS were prepared by drying 20mul of specimen overnight at room temperature. The addition of a green dye (0.1%) made the DTS pellets visible without affecting the test results. Before testing, the DTS were rehydrated with 200mul of PBS/Tween buffer. A panel of 303 DTS samples (135 HIV positive and 168 negative) was evaluated with two rapid tests. Sensitivity and specificity with the Determine HIV-1/2 test were 99.3% and 99.4%, respectively, and with OraQuick were 98.5% and 100%, respectively. Stability studies showed that HIV-specific antibodies in the DTS specimens were stable at 4 degrees and 25 degrees for 4 weeks, with only marginal decline at 37 degrees and 45 degrees C over 4 weeks. The DTS-based PT program was piloted successfully in 24 testing sites in Kenya. Results demonstrate that the DTS is a simple to use, practical method to prepare and distribute PT panels and quality control specimens to monitor HIV testing practices in RLS. |
A public health approach to rapid scale-up of free antiretroviral treatment in China: an ounce of prevention is worth a pound of cure
Bulterys M , Vermund SH , Chen RY , Ou CY . Chin Med J (Engl) 2009 122 (11) 1352-5 China's rapidly evolving HIV/AIDS epidemic calls for a dramatic expansion of both prevention and treatment services.1,2 Official state media recently reported that for the first time, in 2008, HIV/AIDS became China's leading cause of death among infectious diseases.3 Estimates from the Ministry of Health indicate that around 700 000 people were living with HIV and 85 000 people had AIDS in 2007.4 Initially, HIV-1 infection was confined primarily to certain high-risk populations such as injection drug users (IDU) along drug-trafficking routes, and former plasma donors (FPD) in rural communities in east-central China.1,5–7 Now, however, HIV prevalence is increasing among female sex workers (FSW) and men who have sex with men (MSM).4,8 It is estimated that in 2008, approximately 45% of new HIV cases in China were attributed to heterosexual transmission and 12% to MSM; the proportion of women infected has also doubled in the past decade. | To respond effectively to the urgent need of patients with advanced HIV disease, the Chinese government in 2003 started the National Free Antiretroviral Treatment Program (NFATP). Initially focused on FPD in rural communities,6 this program has since expanded to all 31 provinces. In 2009, the government announced that second-line antiretroviral treatment (ART) — at a cost of approximately $1760 per patient per year — will be provided free to AIDS patients who have become resistant to first-line ART.9 In this issue of the Chinese Medical Journal, investigators and leaders from the National Center for AIDS/STD Control and Prevention (NCAIDS) at the Chinese Center for Disease Control and Prevention describe the formidable challenges in rolling out ART to all those who need it.10 They highlight ethical considerations in distributing the benefits of ART equitably in the context of seeking to minimize development of multi-drug resistant HIV strains. The authors conclude that the aim of universal access to ART is achievable in China with additional and innovative strategies. |
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