Opportunities to improve storage and transportation of blood specimens for CD4 testing in a rural district in Zimbabwe using BD vacutainer CD4 stabilization tubes: a stability and diagnostic accuracy study

BMC Infectious Diseases

Helen Bygrave³  Misheck Kuhudzayi¹  Sandra Simons⁴  Dhodho Munyaradzi²  Charlotte van Vyve²  Elton Mbofana²  Carol Metcalf³  Emmanuel Fajardo³ 

[1] Ministry of Health and Child Welfare Zimbabwe, Buhera District, Zimbabwe;Médecins Sans Frontières, Buhera District, Buhera, Zimbabwe;Médecins Sans Frontières, Southern Africa Medical Unit, Wyecroft Road, Waverley Business Park, Block 20, Suites 303 A&B, Mowbray 7925, Cape Town, South Africa;Médecins Sans Frontières, Harare, Zimbabwe

关键词: Zimbabwe;    Resource-limited settings;    Specimen transport;    Antiretroviral therapy;    CD4+ T-cell testing;   

Others  :  1122194
DOI  :  10.1186/s12879-014-0553-9

 received in 2014-04-03, accepted in 2014-10-10,  发布年份 2014

【 摘 要 】

Background

CD4+ T-cell testing of blood specimens collected in standard EDTA Vacutainer tubes and transported at ambient temperature, must be completed within 48 hours with the BD FACSCount™ flow cytometer, restricting specimen collection in remote clinics with no on-site testing and limited specimen transport services. We conducted a study in Buhera District, Zimbabwe, to assess the stability and accuracy of CD4+ T-cell results of samples collected in Stabilization Tubes (ST) and stored at ambient temperature for varying time periods.

Methods

Paired EDTA and ST samples were collected from 51 HIV-positive patients aged 18 years and older. CD4+ T-cell testing was done on arrival in the laboratory (Day 0). ST samples were retested on Days 3, 5, and 7. Nineteen ST samples were stored for an additional week and retested on Day 14.

Results

There was a strong correlation between absolute CD4+ T-cell counts measured in the EDTA Day 0 reference sample and Day 7 ST sample (Spearman’s rho: 0.9778; mean difference: −4.9 cells/μL and limits of agreement (LOA): 98.5 and 88.7 cells/μL); and the reference sample and Day 14 ST sample (Spearman’s rho: 0.9632; mean difference 5.1 cells/μL and LOA: −99.6 and 109.8 cells/μL. Using a 350 cells/μL threshold, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were all 100% on Day 7, and 83.3%, 100%, 100% and 92.9% on Day 14. Using a 500 cells/μL threshold, the sensitivity, specificity, PPV and NVP were 100%, 88.5%, 88.5% and 100% on Day 7 and 88.9%, 80.0%, 80.0% and 88.9% on Day 14.

Conclusions

CD4 ST can be used and stored up to 7 days as a reliable alternative to standard EDTA tubes in settings where CD4+ T-cell testing within 48 hours is not feasible. Despite the small sample size, results suggest that ST may be stored up to 14 days at room temperature for CD4 testing, without compromising accuracy. However, further studies with larger sample sizes are needed to confirm this preliminary finding.

【 授权许可】

   
2014 Fajardo et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

Figure 2.

【 参考文献 】

• [1]World Health Organization: Consolidated Guidelines on the Use of Antiretroviral Drugs for Treating and Preventing HIV Infection. Recommandations for a Public Health Approach. 2013
• [2]World Health Organization: Guidelines on Co-trimoxazole prophylaxis for HIV-related infections among children, adolescents and adults. Recommendations for a Public Health Approach. 2006
• [3]World Health Organization: Rapid Advice. Diagnosis, Prevention and Management of Cryptococcal Disease in HIV-infected Adults, Adolescents and Children. 2011
• [4]The National Medicine and Therapeutics Policy Advisory Committee (NMTPAC) and The AIDS and TB Directorate, Ministry of Health and Child Care (MOHCC), Harare, Republic of Zimbabwe: Guidelines for Antiretroviral Therapy for the Prevention and Treatment of HIV in Zimbabwe. 2013
• [5]Peter T, Badrichani A, Wu E, Freeman R, Ncube B, Ariki F, Daily J, Shimada Y, Murtagh M: Challenges in implementing CD4 testing in resource-limited settings. Cytometry B Clin Cytom 2008, 74(Suppl 1):S123-S130.
• [6]Bélec L, Bonn JP: Challenges in implementing HIV laboratory monitoring in resource-constrained settings: how to do more with less. Future Microbiol 2011, 6(11):1251-1260.
• [7]HIV/AIDS Diagnostics Technology Landscape. 2012.
• [8]1997 revised guidelines for performing CD4+ T-cell determinations in persons infected with human immunodeficiency virus (HIV). Centers for Disease Control and Prevention MMWR Recomm Rep 1997, 46:1-29.
• [9]Micek MA, Gimbel-Sherr K, Baptista AJ, Matediana E, Montoya P, Pfeiffer J, Melo A, Gimbel-Sherr S, Johnson W, Gloyd S: Loss to follow-up of adults in public HIV care systems in central Mozambique: identifying obstacles to treatment. J Acquir Immune Defic Syndr 2009, 52(3):397-405.
• [10]Losina E, Bassett IV, Giddy J, Chetty S, Regan S, Walensky RP, Ross D, Scott CA, Uhler LM, Katz JN, Holst H, Freedberg KA: The “ART” of linkage: pre-treatment loss to care after HIV diagnosis at two PEPFAR sites in Durban, South Africa. PLoS One 2010, 5:e9538.
• [11]Wynberg E, Cooke G, Shroufi A, Reid SD, Ford N: Impact of point-of-care CD4 testing on linkage to HIV care: a systematic review. J Int AIDS Soc 2014, 17(1):18809.
• [12]Larson B, Schnippel K, Ndibongo B, Long L, Fox MP, Rosen S: How to estimate the cost of point-of-care CD4 testing in program settings: an example using the Alere Pima Analyzer in South Africa. PLoS One 2012, 7(4):e35444.
• [13]Jani V, Janossy G, Iqbal A, Mhalu FS, Lyamuya EF, Biberfeld G, Glencross DK, Scott L, Reilly JT, Granger V, Barnett D: Affordable CD4+ T cell counts by flow cytometry. II. The use of fixed whole blood in resource-poor settings. J Immunol Methods 2001, 257(1–2):145-154.
• [14]Warrino DE, DeGennaro LJ, Hanson M, Swindells S, Pirruccello SJ, Ryan WL: Stabilization of white blood cells and immunologic markers for extended analysis using flow cytometry. J Immunol Methods 2005, 305(2):107-119.
• [15][http:/ / www.bd.com/ contentmanager/ b_article.asp?Item_ID=22662&Content Type_ID=1&BusinessCode=20001&d=&s=& dTitle=&dc=&dcTitle] webcite Beckton Dickinson Diagnostics: BD Diagnostics Announces Availability in Africa of New CD4 Stabilization Blood Collection Technology. Available at: =
• [16]Shott JP, Iga B, Makumbi F, Luswata C, Kagulire C, Nammanda J, Mills LA, Serwadda D, Quinn TC, Reynolds SJ: CD4 stabilization tubes provide improved accuracy of absolute CD4 T-cell counts compared to standard k3 EDTA tubes in human immunodeficiency virus immunologic monitoring in resource-poor settings. Clin Vaccine Immunol 2008, 15(10):1623-1624.
• [17]Bland JM, Altman DG: Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986, 1:307-310.
• [18]Diaw PA, Daneau G, Coly AA, Ndiaye BP, Wade D, Camara M, Mboup S, Kestens L, Dieye TN: Multisite evaluation of a point-of-care instrument for CD4(+) T-cell enumeration using venous and finger-prick blood: the PIMA CD4. J Acquir Immune Defic Syndr 2011, 58(4):e103-e111.
• [19]Varro R, Bui N, Warns MT, Campbell G, Pfeltz RF, Bush C: Methods to increase the accuracy of the%CD4 T cell count in pediatric specimens from resource limited settings.In AIDS 2010 - XVIII International AIDS Conference: Abstract no. THPE0439
• [20]Das GA: Distant testing in laboratory hematology and flow cytometry- the Indian experience. Clin Lab Med 2012, 32(2):301-314.
• [21]World Health Organization: Supplement to the 2013 consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection. Recommendations for a public health approach. Geneva: 2014
• [22]Kiyaga C, Sendagire H, Joseph E, McConnell I, Grosz J, Narayan V, Esiru G, Elyanu P, Akol Z, Kirungi W, Musinguzi J, Opio A: Uganda’s new national laboratory sample transport system: a successful model for improving access to diagnostic services for Early Infant HIV Diagnosis and other programs. PLoS One 2013, 8(11):e78609.
• [23][http://www.unicef.org/evaldatabase/index_69965.html] webcite Ministry of Health and Child Welfare, Zimbabwe: An Evaluation of the Use of Point of Care PIMA CD4 Cell Count Machines for HIV Positive Women and their Families in Maternal Newborn And Child Health (MNCH) Settings in Seven Districts in Zimbabwe, 2012. Available at:
• [24]Shephard MD, Mazzachi BC, Watkinson L, Shephard AK, Laurence C, Gialamas A, Bubner T: Evaluation of a training program for device operators in the Australian Government’s Point of Care Testing in General Practice Trial: issues and implications for rural and remote practices. Rural Remote Health 2009, 9(3):1189.
• [25]Glencross DK, Coetzee LM, Faal M, Masango M, Stevens WS, Venter WF, Osih R: Performance evaluation of the Pima™ point-of-care CD4 analyser using capillary blood sampling in field tests in South Africa. J Int AIDS Soc 2012, 15(1):3. BioMed Central Full Text