Validation of a screening tool to identify older children living with HIV in primary care facilities in high HIV prevalence settings

Objective: We previously proposed a simple tool consisting of five items to screen for risk of HIV infection in adolescents (10-19 years) in Zimbabwe. The objective of this study is to validate the performance of this screening tool in children aged 6-15 years attending primary healthcare facilities in Zimbabwe. Methods: Children who had not been previously tested for HIV underwent testing with caregiver consent. The screening tool was modified to include four of the original five items to be appropriate for the younger age range, and was administered. A receiver operator characteristic analysis was conducted to determine a suitable cut-off score. The sensitivity, specificity and predictive value of the modified tool were assessed against the HIV test result. Results: A total of 9568 children, median age 9 (interquartile, IQR: 7-11) years and 4971 (52%) men, underwent HIV testing. HIV prevalence was 4.7% (95% confidence interval, CI:4.2-5.1%) and increased from 1.4% among those scoring zero on the tool to 63.6% among those scoring four (P < 0.001). Using a score of not less than one as the cut-off for HIV testing, the tool had a sensitivity of 80.4% (95% CI:76.5-84.0%), specificity of 66.3% (95% CI:65.3-67.2%), positive predictive value of 10.4% and a negative predictive value of 98.6%. The number needed to screen to identify one child living with HIV would drop from 22 to 10 if this screening tool was used. Conclusion: The screening tool is a simple and sensitive method to identify children living with HIV in this setting. It can be used by lay healthcare workers and help prioritize limited resources.