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Updated: Jul 6, 2026
The α-test: Rapid Cell-free CD4 Enumeration Using Whole Saliva
Published on: May 16, 2012
Computed CD4 percentage as a low-cost method for determining pediatric antiretroviral treatment eligibility
Steven F J Callens1, Faustin Kitetele, Jean Lusiama
1Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, USA. callens@email.unc.edu
Insights
Pediatric antiretroviral treatment (ART) eligibility criteria show poor agreement. A simple CD4 percent estimate improves access to ART for children in resource-limited settings.
Area of Science:
- Pediatric Infectious Diseases
- Immunology
- Public Health
Background:
- Documentation of World Health Organization (WHO) pediatric antiretroviral treatment (ART) performance in resource-limited settings is scarce.
- Routine care data is crucial for evaluating ART effectiveness in children.
Purpose of the Study:
- To compare clinical and immunological criteria for pediatric ART eligibility.
- To evaluate a simple computational method for estimating CD4 percentage.
- To assess ART access barriers in resource-poor settings.
Main Methods:
- Compared clinical and immunological criteria in 366 children (0-12 years) in Kinshasa.
- Evaluated a CD4 percentage estimation formula using CD4 count, white blood cell count, and lymphocyte percentage.
- Utilized Kappa statistic for eligibility criteria agreement and linear regression for trend analysis.
Main Results:
- Poor agreement (kappa = 0.26) between clinical and immunological ART eligibility criteria.
- Significant discordance: one-third of children were eligible by one criterion but not the other.
- Substantial agreement (kappa = 0.71) for the CD4 percentage computational estimate compared to direct measurement.
- Age-specific trends observed in CD4 count and percentage.
Conclusions:
- Age-specific CD4 percentage thresholds are optimal for determining pediatric ART eligibility.
- A CD4 percentage computational estimate can enhance ART accessibility where CD4 assays are limited.
Background:
The performance of the WHO recommendations for pediatric antiretroviral treatment (ART) in resource poor settings is insufficiently documented in routine care.
Methods:
We compared clinical and immunological criteria in 366 children aged 0 to 12 years in Kinshasa and evaluated a simple computation to estimate CD4 percent, based on CD4 count, total white blood cell count and percentage lymphocytes. Kappa (kappa) statistic was used to evaluate eligibility criteria and linear regression to determine trends of CD4 percent, count and total lymphocyte count (TLC).
Results:
Agreement between clinical and immunological eligibility criteria was poor (kappa = 0.26). One third of children clinically eligible for ART were ineligible using immunological criteria; one third of children immunologically eligible were ineligible using clinical criteria. Among children presenting in WHO stage I or II, 54 (32%) were eligible according to immunological criteria. Agreement with CD4 percent was poor for TLC (kappa = 0.04), fair for total CD4 count (kappa = 0.39) and substantial for CD4 percent computational estimate (kappa = 0.71). Among 5 to 12 years old children, total CD4 count was higher in younger age groups (-32 cells/mm3 per year older), CD4 percent was similar across age groups.
Conclusion:
Age-specific thresholds for CD4 percent optimally determine pediatric ART eligibility. The use of CD4 percent computational estimate may increase ART access in settings with limited access to CD4 percent assays.
