A quality management systems approach for CD4 testing in resource-poor settings

Evaluation of a collaborative model for successful implementation of a National CD4 enumeration EQA program in Cameroon

Participation in an EQA program is critical to the quality assurance process. Reliable and precise CD4 T-cells enumeration are essential to improve the clinical management of patients by evaluating the disease progression and by monitoring the effectiveness of ART in HIV-patients. The CIRCB, CD4 reference laboratory, in collaboration with the Canadian QASI-program, recruited sites, distributed and analyzed CD4-panels in 61 sites across Cameroon. A trend and performance analysis in the pre-analytical, analytical and post-analytical phases was performed. Continuous training and corrective actions carried out from 2014 to 2018 increased the number of participating sites from 15 to 61 sites, the number of unacceptable results decreased from 50 to 10%. Specific challenges included errors in pre analytic (17.5%), analytic (77.0%) and post-analytic (5.5%) phases. This EQA requires the application of good laboratory practices, fluidic communication between all the stakeholders, continuous training, application of specific on-site corrective measures, and timely equipment maintenance in order to avoid repetitive errors and to increase laboratory performance. It could be extended to other HIV-1 testing like viral load and EID point-of-care. Partnership with QASI serve as a model for implementation of a successful EQA model for resource limited countries wanting to implement EQA for HIV testing and monitoring in alignment with 90–90–90 targets.

External Quality Assessment on CD4+ T-Cell Count Using in-House Proficiency Testing Panels for CD4 Count Laboratories in Addis Ababa, Ethiopia

Background

CD4+ T-cell count External Quality Assessment program is important for the evaluation of performance of CD4 count laboratories. The aim of this study was to assess the quality of CD4count laboratory performance using in-house Proficiency testing panels that perform routine CD4 counts in Addis Ababa, Ethiopia, 2013/14.

Methods

Participating laboratories were 20, 23 and 25 in trials 1, 2 and 3, respectively. In-house prepared fresh whole blood samples both with “normal” and “low” CD4 values were sent to participating laboratories. Percentage and absolute counts of CD4+ T-lymphocytes were done using their routine procedures. Data were analyzed for each trial including trimmed mean, standard deviation (SD), percent coefficient of variation (%CV), residual, and standard deviation index (SDI) values for both absolute counts and percentages of CD4+ lymphocytes (%CD4).

Results

Most participating laboratories produced results that were within 2SD of the mean. Average inter-laboratory precision (trimmed %CV) was 10.87% and 5.14% for CD4 absolute counts and %CD4, respectively. For normal material, the trimmed mean %CV was 9.59% and3.23% for CD4 absolute counts and %CD4, respectively. For low material, the trimmed mean % CV was 12.15% and 7.05% for CD4 absolute counts and %CD4 respectively. BDFACSCount™ users showed the best accuracy and precision as evidenced by longitudinal analysis.

Conclusion

This study was found to help facilities in early identifying their gaps with regard to their CD4 count performance and in avoiding the challenges encountered during participation in external EQA providers like the high cost, transportation problem, feedback delay and CD4laboratory coverage.

Onsite healthcare worker acceptability and performance of the point-of-care Pima CD4 assay in Dar es Salaam, Tanzania

Background: Healthcare workers’ acceptance of and ability to perform point-of-care testing is important for reliable and accurate results. The Alere Pima™ CD4 assay (Pima CD4) is the CD4 point-of-care test for HIV management in Tanzania.Objectives: To evaluate healthcare workers’ acceptance and performance of Pima CD4 testing.Methods: The study was implemented in five high volume sites in Dar es Salaam, Tanzania, in 2011. Trained healthcare workers performed Pima testing using three whole-blood specimens collected from each patient: venous blood, fingerstick blood directly applied to a Pima cartridge (capillary-direct), and fingerstick blood collected in a microtube (capillary-microtube). Using a semi-structured interview guide, we interviewed 11 healthcare workers about specimen collection methods and Pima CD4 acceptability. Quantitative responses were analysed using descriptive statistics. Open-ended responses were summarised by thematic areas. Pima CD4 results were analysed to determine variation between cadres.Results: Healthcare workers found Pima CD4 user-friendly and recommended its use in low volume, peripheral facilities. Both venous and capillary-direct blood were considered easy to collect, with venous preferred. Advantages noted with venous and capillary-microtube methods were the ability to retest, perform multiple tests, or delay testing. Pima CD4 results were trusted by the healthcare workers and were in agreement with laboratory Pima testing.Conclusion: In this point-of-care testing setting, the Pima CD4 assay was accepted by healthcare workers. Both venous and fingerstick capillary blood specimens can be used with Pima CD4, but fingerstick methods may require more intensive training on technique to minimise variation in results and increase acceptability.

Quality assurance for HIV point-of-care testing and treatment monitoring assays

In 2015, UNAIDS launched the 90-90-90 targets aimed at increasing the number of people infected with HIV to become aware of their status, access antiretroviral therapies and ultimately be virally suppressed. To achieve these goals, countries may need to scale up point-of-care (POC) testing in addition to strengthening central laboratory services. While decentralising testing increases patient access to diagnostics, it presents many challenges with regard to training and assuring the quality of tests and testing. To ensure synergies, the London School of Hygiene & Tropical Medicine held a series of consultations with countries with an interest in quality assurance and their implementing partners, and agreed on an external quality assessment (EQA) programme to ensure reliable results so that the results lead to the best possible care for HIV patients. As a result of the consultations, EQA International was established, bringing together EQA providers and implementers to develop a strategic plan for countries to establish national POC EQA programmes and to estimate the cost of setting up and maintaining the programme. With the dramatic increase in the number of proficiency testing panels required for thousands of POC testing sites across Africa, it is important to facilitate technology transfer from global EQA providers to a network of regional EQA centres in Africa for regional proficiency testing panel production. EQA International will continue to identify robust and cost-effective EQA technologies for quality POC testing, integrating novel technologies to support sustainable country-owned EQA programmes in Africa.

Implementing Laboratory Quality Management Systems in Mozambique: The Becton Dickinson-US President's Emergency Plan for AIDS Relief Public-Private Partnership Initiative

BACKGROUND

Mozambique's ministry of health (MOH) recognized the need to establish a national laboratory quality assurance (NLQA) program to improve the reliability and accuracy of laboratory testing. The Becton Dickinson-US President's Emergency Plan for AIDS Relief Public-Private Partnership (PPP) was used to garner MOH commitment and train a cadre of local auditors and managers to support sustainability and country ownership of a NLQA program.

METHODS

From January 2011 to April 2012, the World Health Organization Regional Office for Africa Stepwise Laboratory Quality Improvement Process Towards Accreditation (SLIPTA) checklist and the Strengthening Laboratory Management Towards Accreditation (SLMTA) curriculum were used in 6 MOH laboratories. PPP volunteers provided training and mentorship to build the capacity of local auditors and program managers to promote institutionalization and sustainability of the program within the MOH.

RESULTS

SLIPTA was launched in 6 MOH laboratories, and final audits demonstrated improvements across the 13 quality system essentials, compared with baseline. Training and mentorship of MOH staff by PPP volunteers resulted in 18 qualified auditors and 28 managers/quality officers capacitated to manage the improvement process in their laboratories.

CONCLUSIONS

SLIPTA helps laboratories improve the quality and reliability of their service even in the absence of full accreditation. Local capacity building ensures sustainability by creating country buy-in, reducing costs of audits, and institutionalizing program management.

Improved Specimen-Referral System and Increased Access to Quality Laboratory Services in Ethiopia: The Role of the Public-Private Partnership

BACKGROUND

Nonstandardized specimen-transport logistics, lack of laboratory personnel to transport specimens, lack of standard specimen containers, and long turnaround time (TAT) hindered access to quality laboratory services. The objective of the Becton, Dickinson, and Company (BD)-US President's Emergency Plan for AIDS Relief (PEPFAR) Public-Private Partnership (PPP) was to support country-specific programs to develop integrated laboratory systems, services, and quality improvement strategies, with an emphasis on strengthening the specimen-referral system (SRS).

METHODS

In 2007, through the Centers for Disease Control and Prevention (CDC), the Ethiopian Public Health Institute (EPHI) joined with the BD-PEPFAR PPP to strengthen laboratory systems. A joint planning and assessment committee identified gaps in the SRS for prioritization and intervention and piloted the system in Addis Ababa and Amhara Region.

RESULTS

The PPP established standardized, streamlined specimen logistics, using the Ethiopian Postal Service Enterprise to support a laboratory network in which 554 facilities referred specimens to 160 laboratories. The PPP supported procuring 400 standard specimen containers and the training of 586 laboratory personnel and 81 postal workers. The average TAT was reduced from 7 days (range, 2-14 days) to 2 days (range, 1-3 days) in Addis Ababa and from 10 days (range, 6-21 days) to 5 days (range, 2-6 days) in Amhara Region.

CONCLUSIONS

This study highlights the feasibility and untapped potential of PPPs to strengthen laboratory systems. This planned and structured approach to improving specimen referral enhanced access to quality laboratory services.

Preparation of Internal Quality Control Material for Lymphocyte Subset Analysis

Lymphocyte subset analysis is widely used in clinical laboratories, and more than two levels of daily QC materials are required for reliable results. Commercially available, expensive QC materials have short shelf lives and may not be suitable in resource-poor settings. We compared different methods for preparing homemade QC material, including fixation with 1%, 2%, or 4% paraformaldehyde (PFA); freezing with 10% dimethylsulfoxide (DMSO), 0.1% bovine serum albumin-phosphate buffered saline, or after ethanolic dehydration; and using cryopreservation temperatures of -20℃, -80℃, or -196℃. We found an optimal experimental condition, which is 'fixation with 4% PFA, freezing with 10% DMSO, and storage at 80℃'. To evaluate long-term stability of QC materials prepared in this optimal condition, two levels of QC materials (QM1 and QM2) were thawed after 30, 33, 35, 37, 60, 62, 64, and 67 days of cryopreservation. Lymphocyte subset was analyzed with BD Multitest IMK kit (BD Biosciences, USA). QM1 and QM2 were stable after 1-2 months of cryopreservation (CV <3% for CD3, CD4, and CD8 and 5-7% for CD16/56 and CD19). We propose this method as an alternative cost-effective protocol for preparing homemade internal QC materials for lymphocyte subset analysis in resource-poor settings.

Duplicate analysis method: a cheaper alternative to commercial IQC materials in limited resource settings for monitoring CD4 testing

BACKGROUND

India has a large number of HIV infected patients being followed up at anti-retroviral therapy (ART) centers. The patients are regularly offered CD4 count estimation for deciding their eligibility for ART initiation as well as for monitoring response to ART, making CD4 count estimation a very critical test. Hence, quality control of CD4 testing is utmost important for ultimate success of ART program. As the commercial controls are very expensive, internal quality control (IQC), at present, is being done by duplicate analysis method using previous day samples in most of the laboratories. Hence the study was undertaken to review performance of duplicate analysis method for monitoring daily IQC.

METHODS

Quality control (QC) data from 11 Indian laboratories using duplicate analysis and/or commercial controls for IQC of CD4 testing was collected for reviewing information on QC parameters such as precision, accuracy and trend monitoring. Precision was determined by r(2) values and mean % variation for duplicate analysis and coefficient of variation (% CV) for commercial controls. Accuracy was monitored by rate of QC failures for both the types of control and trend monitoring was done by plotting LJ charts for commercial controls and by plotting daily % variation for duplicate analysis.

RESULTS

The laboratories using duplicate analysis for IQC showed good precision with mean % variation ranging from 0.5 to 7.2. There was good match between r(2) values and % CV of the laboratories performing both the types of QC methods. Rates of QC failures were 2.3 for duplicate analysis and 3 per laboratory-year for IMMUNO-TROL controls. Daily trend monitoring showed fluctuation of daily counts around mean in LJ charts and of percent variation around 0% in duplicate analysis method. Commercially available controls showed limitations such as altered specimen quality leading to difficulties in manual gating and issues with the establishment of laboratory range.

CONCLUSION

Duplicate analysis can serve as a cheaper alternative to commercially available controls for IQC of CD4 testing especially when supplemented with other QC measures for controlling variations caused by reagent, equipment, staff and environment in addition to the successful participation in External Quality Assurance programme.

Compatibility of stabilized whole blood products with CD4 technologies and their suitability for quality assessment programs

BACKGROUND

CD4 T cell enumeration is the most widely used prognostic marker for management of HIV disease. Internal quality control and external quality assessment (EQA) programs are critical to ensure reliability of clinical measurements. The utility of stabilized whole blood products (SWBP) as a test reagent for EQA programs such as Quality Assessment and Standardization for Immunological measures relevant to HIV/AIDS (QASI) program have been demonstrated previously. Since then, several new commercial SWBPs and alternative CD4 enumeration technologies have become available. Seven SWBPs were evaluated on seven different enumeration platforms to determine which product(s) are most suitable for EQA programs that support multiple analytical technologies.

METHOD

Assessment of SWBPs was based on two criteria: (1) accuracy of CD4 T cell measurements and; (2) stability under sub optimal storage conditions.

RESULTS

Three SWBPs (Multi-Check, StatusFlow and CD4 Count) showed accurate CD4 T-cell absolute count and percentage values across six of the enumeration platforms. All products retain stability up to 18 days at 21-23°C with the exception of Multi-Check-high on FacsCount and Multi-Check-Low and StatusFlow-Low on Pima. One of the products (CD4 Count) retained stability for three days on all platforms tested when stored at 37°C.

CONCLUSION

This study demonstrated that the characteristics of commercially available SWBPs vary across multiple CD4 platforms. The compatibility of testing panels for EQA programs with multiple analytical platforms needs to be carefully considered, especially in large multiplatform CD4 EQA programs. The selection of a suitable cross-platform SWBP is an increasing challenge as more reagents and platforms are introduced for CD4 T-cell enumeration.

Population-based CD4 counts in a rural area in South Africa with high HIV prevalence and high antiretroviral treatment coverage

Background

Little is known about the variability of CD4 counts in the general population of sub-Saharan Africa countries affected by the HIV epidemic. We investigated factors associated with CD4 counts in a rural area in South Africa with high HIV prevalence and high antiretroviral treatment (ART) coverage.

Methods

CD4 counts, health status, body mass index (BMI), demographic characteristics and HIV status were assessed in 4990 adult resident participants of a demographic surveillance in rural KwaZulu-Natal in South Africa; antiretroviral treatment duration was obtained from a linked clinical database. Multivariable regression analysis, overall and stratified by HIV status, was performed with CD4 count levels as outcome.

Results

Median CD4 counts were significantly higher in women than in men overall (714 vs. 630 cells/µl, p<0.0001), both in HIV-uninfected (833 vs. 683 cells/µl, p<0.0001) and HIV-infected adults (384.5 vs. 333 cells/µl, p<0.0001). In multivariable regression analysis, women had 19.4% (95% confidence interval (CI) 16.1–22.9) higher CD4 counts than men, controlling for age, HIV status, urban/rural residence, household wealth, education, BMI, self-reported tuberculosis, high blood pressure, other chronic illnesses and sample processing delay. At ART initiation, HIV-infected adults had 21.7% (95% CI 14.6–28.2) lower CD4 counts than treatment-naive individuals; CD4 counts were estimated to increase by 9.2% (95% CI 6.2–12.4) per year of treatment.

Conclusions

CD4 counts are primarily determined by sex in HIV-uninfected adults, and by sex, age and duration of antiretroviral treatment in HIV-infected adults. Lower CD4 counts at ART initiation in men could be a consequence of lower CD4 cell counts before HIV acquisition.

Decentralization of CD4 testing in resource-limited settings: 7 years of experience in six African countries

Improving access to CD4 testing in resource-limited settings can be achieved through both centralized and decentralized testing networks. Decentralized testing models are more suitable for countries where the HIV epidemic affects a large portion of rural populations. Timely access to accurate CD4 results is crucial at the primary level of the health system. For the past 7 years, the Institute of Human Virology of the University of Maryland School of Medicine has implemented a flexible and sustainable three-phase model: (1) site assessment and improvement, (2) appropriate technology selection with capacity building through practical training and laboratory mentoring, and (3) quality management system strengthening and monitoring, to support accessibility to reliable CD4 counting at the point of service. CD4 testing capacity was established in 122 of 229 (53%) laboratories supported in Nigeria, Uganda, Kenya, Zambia, Tanzania, and Rwanda. Among those in rural settings, 46% (69/151) had CD4 testing available at site level, with a functioning flow cytometer installed at 28% (8/29) and 50% (61/122) of level 1 and level 2 sites, respectively. To strengthen local capacity, a total of 1,152 laboratory technicians were trained through 188 training sessions provided both on-site and at central locations. The overall quality of CD4 total testing procedure was assessed at 76% (92/121) of the laboratories, with 25% (23/92), 34% (31/92), and 33% (30/92) of them reporting excellent, good, and satisfactory performance. Balancing country-specific factors with the location of the clinic, number of patients, and the expected workload, was crucial in adapting this flexible model for decentralizing CD4 testing. The close collaboration with local governments and private vendors was key to successfully expanding access to CD4 testing within the framework of HIV care and treatment programs and for the sustainability of medical laboratories in resource-limited settings.