Evaluation of a low-cost method, the Guava EasyCD4 assay, to enumerate CD4-positive lymphocyte counts in HIV-infected patients in the United States and Uganda

Lisa A. Spacek, Hasan M. Shihab, Fred Lutwama, Jean Summerton, Harriet Mayanja, Allan Ronald, Joseph Bernard Margolick, Tricia L. Nilles, Thomas C Quinn

Research output: Contribution to journalArticle

Abstract

Objective: To evaluate the EasyCD4 assay, a less expensive method to enumerate CD4+ lymphocytes, in resource-limited settings. Design: Cross-sectional study conducted in the United States and Uganda. Methods: We compared CD4+ cell counts obtained on replicate samples from HIV-infected patients by the EasyCD4 assay, a microcapillary flow-based system, and by standard flow cytometry or FACSCount with linear regression and the Bland-Altman method. Results: Two hundred eighteen samples were analyzed (77 in the United States and 141 in Uganda). In the United States, mean ± SD CD4 was 697 ± 438 cells/μL by standard flow cytometry and 688 ± 451 cells/μL by EasyCD4. In Uganda, the mean ± SD CD4 was 335 ± 331 cells/μL by FACSCount and 340 ± 327 cells/μL by EasyCD4. The 2 methods were highly correlated (US cohort, r2 = 0.97, slope = 1.0, intercept = -18; Ugandan cohort, r2 = 0.92; slope = 0.95; intercept = 23). The mean differences in CD4 cell counts were 9.0 and -4.6 cells/μL for the US and Ugandan cohorts, respectively, and they were not significant in either cohort. In the Ugandan cohort, sensitivity and specificity of the EasyCD4 for CD4 below 200 cells/ μL were 90% and 98%, respectively. Positive predictive value was 96%; negative predictive value was 93%. Conclusions: Our results suggest that EasyCD4 may be used with high positive and negative predictive value in resource-limited settings.

Original languageEnglish (US)
Pages (from-to)607-610
Number of pages4
JournalJournal of Acquired Immune Deficiency Syndromes
Volume41
Issue number5
DOIs
StatePublished - Apr 2006

Fingerprint

Psidium
CD4-Positive T-Lymphocytes
Uganda
CD4 Lymphocyte Count
HIV
Costs and Cost Analysis
Flow Cytometry
Linear Models
Cross-Sectional Studies
Lymphocytes
Sensitivity and Specificity

Keywords

  • Antiretroviral therapy resource-limited setting
  • CD4-positive lymphocyte counts
  • Monitoring and evaluation
  • Uganda

ASJC Scopus subject areas

  • Virology
  • Immunology

Cite this

Evaluation of a low-cost method, the Guava EasyCD4 assay, to enumerate CD4-positive lymphocyte counts in HIV-infected patients in the United States and Uganda. / Spacek, Lisa A.; Shihab, Hasan M.; Lutwama, Fred; Summerton, Jean; Mayanja, Harriet; Ronald, Allan; Margolick, Joseph Bernard; Nilles, Tricia L.; Quinn, Thomas C.

In: Journal of Acquired Immune Deficiency Syndromes, Vol. 41, No. 5, 04.2006, p. 607-610.

Research output: Contribution to journalArticle

Spacek, Lisa A. ; Shihab, Hasan M. ; Lutwama, Fred ; Summerton, Jean ; Mayanja, Harriet ; Ronald, Allan ; Margolick, Joseph Bernard ; Nilles, Tricia L. ; Quinn, Thomas C. / Evaluation of a low-cost method, the Guava EasyCD4 assay, to enumerate CD4-positive lymphocyte counts in HIV-infected patients in the United States and Uganda. In: Journal of Acquired Immune Deficiency Syndromes. 2006 ; Vol. 41, No. 5. pp. 607-610.
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abstract = "Objective: To evaluate the EasyCD4 assay, a less expensive method to enumerate CD4+ lymphocytes, in resource-limited settings. Design: Cross-sectional study conducted in the United States and Uganda. Methods: We compared CD4+ cell counts obtained on replicate samples from HIV-infected patients by the EasyCD4 assay, a microcapillary flow-based system, and by standard flow cytometry or FACSCount with linear regression and the Bland-Altman method. Results: Two hundred eighteen samples were analyzed (77 in the United States and 141 in Uganda). In the United States, mean ± SD CD4 was 697 ± 438 cells/μL by standard flow cytometry and 688 ± 451 cells/μL by EasyCD4. In Uganda, the mean ± SD CD4 was 335 ± 331 cells/μL by FACSCount and 340 ± 327 cells/μL by EasyCD4. The 2 methods were highly correlated (US cohort, r2 = 0.97, slope = 1.0, intercept = -18; Ugandan cohort, r2 = 0.92; slope = 0.95; intercept = 23). The mean differences in CD4 cell counts were 9.0 and -4.6 cells/μL for the US and Ugandan cohorts, respectively, and they were not significant in either cohort. In the Ugandan cohort, sensitivity and specificity of the EasyCD4 for CD4 below 200 cells/ μL were 90{\%} and 98{\%}, respectively. Positive predictive value was 96{\%}; negative predictive value was 93{\%}. Conclusions: Our results suggest that EasyCD4 may be used with high positive and negative predictive value in resource-limited settings.",
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T1 - Evaluation of a low-cost method, the Guava EasyCD4 assay, to enumerate CD4-positive lymphocyte counts in HIV-infected patients in the United States and Uganda

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AU - Shihab, Hasan M.

AU - Lutwama, Fred

AU - Summerton, Jean

AU - Mayanja, Harriet

AU - Ronald, Allan

AU - Margolick, Joseph Bernard

AU - Nilles, Tricia L.

AU - Quinn, Thomas C

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AB - Objective: To evaluate the EasyCD4 assay, a less expensive method to enumerate CD4+ lymphocytes, in resource-limited settings. Design: Cross-sectional study conducted in the United States and Uganda. Methods: We compared CD4+ cell counts obtained on replicate samples from HIV-infected patients by the EasyCD4 assay, a microcapillary flow-based system, and by standard flow cytometry or FACSCount with linear regression and the Bland-Altman method. Results: Two hundred eighteen samples were analyzed (77 in the United States and 141 in Uganda). In the United States, mean ± SD CD4 was 697 ± 438 cells/μL by standard flow cytometry and 688 ± 451 cells/μL by EasyCD4. In Uganda, the mean ± SD CD4 was 335 ± 331 cells/μL by FACSCount and 340 ± 327 cells/μL by EasyCD4. The 2 methods were highly correlated (US cohort, r2 = 0.97, slope = 1.0, intercept = -18; Ugandan cohort, r2 = 0.92; slope = 0.95; intercept = 23). The mean differences in CD4 cell counts were 9.0 and -4.6 cells/μL for the US and Ugandan cohorts, respectively, and they were not significant in either cohort. In the Ugandan cohort, sensitivity and specificity of the EasyCD4 for CD4 below 200 cells/ μL were 90% and 98%, respectively. Positive predictive value was 96%; negative predictive value was 93%. Conclusions: Our results suggest that EasyCD4 may be used with high positive and negative predictive value in resource-limited settings.

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