An Integrated Tiered Service Delivery Model (ITSDM) Based on Local CD4 Testing Demands Can Improve Turn-Around Times and Save Costs whilst Ensuring Accessible and Scalable CD4 Services across a National Programme

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Abstract

Background

The South African National Health Laboratory Service (NHLS) responded to HIV treatment initiatives with two-tiered CD4 laboratory services in 2004. Increasing programmatic burden, as more patients access anti-retroviral therapy (ART), has demanded extending CD4 services to meet increasing clinical needs. The aim of this study was to review existing services and develop a service-model that integrated laboratory-based and point-of-care testing (POCT), to extend national coverage, improve local turn-around/(TAT) and contain programmatic costs.

Methods

NHLS Corporate Data Warehouse CD4 data, from 60–70 laboratories and 4756 referring health facilities was reviewed for referral laboratory workload, respective referring facility volumes and related TAT, from 2009–2012.

Results

An integrated tiered service delivery model (ITSDM) is proposed. Tier-1/POCT delivers CD4 testing at single health-clinics providing ART in hard-to-reach areas (<5 samples/day). Laboratory-based testing is extended with Tier-2/POC-Hubs (processing ≤30–40 CD4 samples/day), consolidating POCT across 8–10 health-clinics with other HIV-related testing and Tier-3/‘community’ laboratories, serving ≤40 health-clinics, processing ≤150 samples/day. Existing Tier-4/‘regional’ laboratories serve ≤100 facilities and process <350 samples/day; Tier-5 are high-volume ‘metro’/centralized laboratories (>350–1500 tests/day, serving ≥200 health-clinics). Tier-6 provides national support for standardisation, harmonization and quality across the organization.

Conclusion

The ITSDM offers improved local TAT by extending CD4 services into rural/remote areas with new Tier-3 or Tier-2/POC-Hub services installed in existing community laboratories, most with developed infrastructure. The advantage of lower laboratory CD4 costs and use of existing infrastructure enables subsidization of delivery of more expensive POC services, into hard-to-reach districts without reasonable access to a local CD4 laboratory. Full ITSDM implementation across 5 service tiers (as opposed to widespread implementation of POC testing to extend service) can facilitate sustainable ‘full service coverage’ across South Africa, and save>than R125 million in HIV/AIDS programmatic costs. ITSDM hierarchical parental-support also assures laboratory/POC management, equipment maintenance, quality control and on-going training between tiers.

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Most cited references 14

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Effect of point-of-care CD4 cell count tests on retention of patients and rates of antiretroviral therapy initiation in primary health clinics: an observational cohort study.

Ilesh Jani, Nádia Sitoe, Eunice Alfai … (2011)

Loss to follow-up of HIV-positive patients before initiation of antiretroviral therapy can exceed 50% in low-income settings and is a challenge to the scale-up of treatment. We implemented point-of-care counting of CD4 cells in Mozambique and assessed the effect on loss to follow-up before immunological staging and treatment initiation. In this observational cohort study, data for enrolment into HIV management and initiation of antiretroviral therapy were extracted retrospectively from patients' records at four primary health clinics providing HIV treatment and point-of-care CD4 services. Loss to follow-up and the duration of each preparatory step before treatment initiation were measured and compared with baseline data from before the introduction of point-of-care CD4 testing. After the introduction of point-of-care CD4 the proportion of patients lost to follow-up before completion of CD4 staging dropped from 57% (278 of 492) to 21% (92 of 437) (adjusted odds ratio [OR] 0·2, 95% CI 0·15-0·27). Total loss to follow-up before initiation of antiretroviral treatment fell from 64% (314 of 492) to 33% (142 of 437) (OR 0·27, 95% CI 0·21-0·36) and the proportion of enrolled patients initiating antiretroviral therapy increased from 12% (57 of 492) to 22% (94 of 437) (OR 2·05, 95% CI 1·42-2·96). The median time from enrolment to antiretroviral therapy initiation reduced from 48 days to 20 days (p<0·0001), primarily because of a reduction in the median time taken to complete CD4 staging, which decreased from 32 days to 3 days (p<0·0001). Loss to follow-up between staging and antiretroviral therapy initiation did not change significantly (OR 0·84, 95% CI 0·49-1·45). Point-of-care CD4 testing enabled clinics to stage patients rapidly on-site after enrolment, which reduced opportunities for pretreatment loss to follow-up. As a result, more patients were identified as eligible for and initiated antiretroviral treatment. Point-of-care testing might therefore be an effective intervention to reduce pretreatment loss to follow-up. Absolute Return for Kids and UNITAID. Copyright © 2011 Elsevier Ltd. All rights reserved.

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Providing immediate CD4 count results at HIV testing improves ART initiation.

Mamsallah Faal, Nicolette Naidoo, Deborah K. Glencross … (2011)

In South Africa, CD4 count results are typically available within a week of testing. However, 35%-55% of newly diagnosed HIV-positive patients do not return for their CD4 results and therefore, do not access further care. We evaluated the impact of a CD4 count result and patient written information provided immediately after diagnosis on retention in care. HIV-infected subjects were randomized to 3 arms; receipt of a CD4 result at time of HIV diagnosis, receipt of written information, and standard of care (CD4 collection after 1 week) or standard of care alone. The outcome of interest was enrollment for further care within 1 month for pre-antiretroviral therapy (ART) care or within 3 months for ART initiation. Secondary outcome was time taken from diagnosis to each stage of care pathway. Independent predictors of retention were assessed with multivariate analysis. Three hundred forty-four patients recruited, of which 64.5% were females with a median age of 30 years (interquartile range: 27-35). Subjects were similar in age, gender, CD4 count, education, and employment status. Providing CD4 results at HIV diagnosis increases the likelihood of reporting for ART initiation (risk ratio = 2.1; 95% confidence interval = 1.39 to 3.17) compared with standard of care. Written information only reduced the time to presentation for pre-ART care although increasing age was associated with retention. There was 49% attrition in the standard of care arms. Receipt of a CD4 count at the time of HIV testing increases ART initiation rates. Point-of-care diagnostics can be used to improve retention, but losses to pre-ART care remain high.

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CD45-assisted PanLeucogating for accurate, cost-effective dual-platform CD4+ T-cell enumeration.

Deborah Kim Glencross, Lesley E. Scott, Ilesh Jani … (2002)

North American and European guidelines for dual-platform (DP) flow cytometry recommend absolute CD4 T-cell counts to be calculated from two parameters: the absolute lymphocyte counts obtained on a hematology analyzer and the percentages of CD4+ cells among lymphocytes (CD4%/lympho) obtained by flow cytometry. Nevertheless, the identification of lymphocytes is error-prone: a poor match between these common denominators in the two systems is the main source of inaccuracy. In contrast, total leucocyte counts (white cell counts [WCC]) and CD4% among the gated CD45+ leucocytes (CD4%/leuco) can be determined with greater accuracy. We introduced "PanLeucogating," i.e., we used total leucocytes as the common denominator for improving the precision of DP absolute CD4 counting. Correlations and Bland-Altman tests were used for statistical analysis. First, 22 stabilized blood product samples were provided by U.K. National External Quality Assessment Scheme (NEQAS) and a higher accuracy and precision of CD4 counts were documented using PanLeucogating compared with lymphocyte gating. Next, 183 fresh and 112 fixed (TransFix) whole blood samples were used to compare DP methods and single-platform (SP) methodology, including both volumetric and bead-based techniques. A particularly high correlation and comparable precision of absolute CD4 counts were observed between the SP volumetric method and DP PanLeucogating (R(2) = 0.990; bias 6 +/- SD 17%). The SP volumetric method showed lower levels of agreement with the DP lymphocyte gating (R(2) = 0.758; bias 14 +/- SD 51%) and with the SP bead-based method (R(2) = 0.923; bias 4 +/-SD 31%). These observations show that DP leucocyte counts (WCC) should replace lymphocyte counts as the "common denominator" although CD4%/lympho values can, as an extra step, be also provided readily if requested. When coupled with quality control for WCC on hematology analyzers, the DP method with CD45 PanLeucogating represents a robust CD4 T-cell assay that is as accurate as the SP volumetric technique. This DP method uses only two, CD45 and CD4, antibody reagents and can be run on any pair of hematological analyzer plus flow cytometer. Copyright 2002 Wiley-Liss, Inc.

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Author and article information

Contributors

David W. Dowdy: Role: Editor

Journal

Journal ID (nlm-ta): PLoS One

Journal ID (iso-abbrev): PLoS ONE

Journal ID (publisher-id): plos

Journal ID (pmc): plosone

Title: PLoS ONE

Publisher: Public Library of Science (San Francisco, USA )

ISSN (Electronic): 1932-6203

Publication date Collection: 2014

Publication date (Electronic): 9 December 2014

Volume: 9

Issue: 12

Electronic Location Identifier: e114727

Affiliations

[1 ]Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

[2 ]Charlotte Maxeke Johannesburg Academic Hospital, National Health Laboratory Service (NHLS), Johannesburg, South Africa

Johns Hopkins Bloomberg School of Public Health, United States of America

Author notes

* E-mail: debbie.glencross@ 123456nhls.ac.za

Competing Interests: The patent for the laboratory CD4 method currently used in laboratories in the National Health Laboratory Service (#EP 1 405 073 B1, and US patent #7670793, entitled: ‘Cell Enumeration’), is wholly owned by the National Health Laboratory Service. In terms of DKG's employment contract with the NHLS, any invention made by DKG during the course of employment is automatically deemed to be owned by the NHLS. As such, DKG is named as the inventor but the patentee is the NHLS. Use of this patented CD4 method in NHLS is not automatic and despite that Beckman Coulter have a licensing agreement with the NHLS, BC is still required, through national government procurement policy, to compete in an open public tender to supply CD4 laboratory testing equipment and reagents. The tender is readvertised and renewed after the expiration period specified for the tender. The authors confirm that this does not alter their adherence to all PLOS ONE policies on sharing data and materials. The remaining authors declare no conflicts of interest.

Conceived and designed the experiments: DKG LMC. Analyzed the data: LMC NC. Contributed reagents/materials/analysis tools: DKG LMC NC. Wrote the paper: DKG LMC NC. Obtained permission to use the NHLS CD4 volumes data: DKG.

Article

Publisher ID: PONE-D-14-20128

DOI: 10.1371/journal.pone.0114727

PMC ID: 4260875

PubMed ID: 25490718

SO-VID: 99a0aa21-fd30-4f13-9019-973b5d774090

License:

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

History

Date received : 13 May 2014

Date accepted : 12 November 2014

Page count

Pages: 21

Funding

The authors have no support or funding to report.

Custom metadata

Data Availability The authors confirm that all data underlying the findings are fully available without restriction. Data was obtained and used with permission of the NHLS CEO (currently Mr Sagie Pillay). Data available to researchers who meet the criteria for access to confidential data and through the NHLS CEO or the COO and the NHLS CDW unit director, (currently Mrs Sue Candy). Address, Private Bag X8, Sandringham 2131. Johannesburg, South Africa Tel: +27 (11) 386-6000.

An Integrated Tiered Service Delivery Model (ITSDM) Based on Local CD4 Testing Demands Can Improve Turn-Around Times and Save Costs whilst Ensuring Accessible and Scalable CD4 Services across a National Programme

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Abstract

Background

Methods

Results

Conclusion

Related collections

PLOS Climate

Most cited references 14

Effect of point-of-care CD4 cell count tests on retention of patients and rates of antiretroviral therapy initiation in primary health clinics: an observational cohort study.

Providing immediate CD4 count results at HIV testing improves ART initiation.

CD45-assisted PanLeucogating for accurate, cost-effective dual-platform CD4+ T-cell enumeration.

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