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

Hdl Handle:
http://hdl.handle.net/10144/334902
Title:
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
Authors:
Fajardo, Emmanuel; Metcalf, Carol; Mbofana, Elton; van Vyve, Charlotte; Munyaradzi, Dhodho; Simons, Sandra; Kuhudzayi, Misheck; Bygrave, Helen
Journal:
BMC Infectious Diseases
Abstract:
BackgroundCD4+ 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.MethodsPaired 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.ResultsThere 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/¿L and limits of agreement (LOA): 98.5 and 88.7 cells/¿L); and the reference sample and Day 14 ST sample (Spearman¿s rho: 0.9632; mean difference 5.1 cells/¿L and LOA: ¿99.6 and 109.8 cells/¿L. Using a 350 cells/¿L 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/¿L 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.ConclusionsCD4 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.
Publisher:
BioMed Central
Issue Date:
22-Oct-2014
URI:
http://hdl.handle.net/10144/334902
DOI:
10.1186/s12879-014-0553-9
PubMed ID:
25330812
Language:
en
ISSN:
1471-2334
Appears in Collections:
HIV/AIDS

Full metadata record

DC FieldValue Language
dc.contributor.authorFajardo, Emmanuelen_GB
dc.contributor.authorMetcalf, Carolen_GB
dc.contributor.authorMbofana, Eltonen_GB
dc.contributor.authorvan Vyve, Charlotteen_GB
dc.contributor.authorMunyaradzi, Dhodhoen_GB
dc.contributor.authorSimons, Sandraen_GB
dc.contributor.authorKuhudzayi, Mishecken_GB
dc.contributor.authorBygrave, Helenen_GB
dc.date.accessioned2014-11-14T17:46:48Z-
dc.date.available2014-11-14T17:46:48Z-
dc.date.issued2014-10-22-
dc.identifier.citationOpportunities 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. 2014, 14 (1):553 BMC Infect. Dis.en_GB
dc.identifier.issn1471-2334-
dc.identifier.pmid25330812-
dc.identifier.doi10.1186/s12879-014-0553-9-
dc.identifier.urihttp://hdl.handle.net/10144/334902-
dc.description.abstractBackgroundCD4+ 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.MethodsPaired 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.ResultsThere 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/¿L and limits of agreement (LOA): 98.5 and 88.7 cells/¿L); and the reference sample and Day 14 ST sample (Spearman¿s rho: 0.9632; mean difference 5.1 cells/¿L and LOA: ¿99.6 and 109.8 cells/¿L. Using a 350 cells/¿L 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/¿L 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.ConclusionsCD4 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.en_GB
dc.languageENG-
dc.language.isoenen
dc.publisherBioMed Centralen_GB
dc.rightsArchived with thanks to BMC Infectious Diseasesen_GB
dc.titleOpportunities 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 studyen
dc.identifier.journalBMC Infectious Diseasesen_GB

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