The reliability of point-of-care CD4 testing in identifying HIV-infected pregnant women eligible for antiretroviral therapy.

OBJECTIVE

Point-of-care (POC) CD4 testing may play an important role in identifying individuals who require antiretroviral therapy (ART), particularly during pregnancy. However, there have been no evaluations of POC CD4 testing in pregnant women. We compared the performance of the PIMA POC analyzer with laboratory-based testing in identifying pregnant women eligible for ART.

DESIGN AND METHODS

Participants were 296 consecutive HIV-infected pregnant women in a prevention of mother-to-child transmission of HIV service in Johannesburg, South Africa. Parallel CD4 cell count testing was done using capillary specimens for the PIMA analyzer and venous samples for flow cytometry.

RESULTS

The median age was 28 years, and the median gestation was 19 weeks (interquartile range, IQR, 16-24). The median PIMA and laboratory CD4 cell counts were 352 cells (IQR, 251-491) cells per cubic millimeter and 367 (IQR, 251-524) cells per cubic millimeter, respectively. The mean difference between the PIMA and the laboratory CD4 results was 20.5 (95% confidence interval: 11.7 to 29.3) cells per cubic millimeter with limits of agreement from -133.9 to 175.0. The PIMA correctly identified 93% of women who were ART eligible based on a laboratory CD4 ≤350 cells per cubic millimeter. There was no evidence of variability in the agreement of PIMA and laboratory-based CD4 testing by participant age or gestation.

CONCLUSIONS

These data show good agreement between the PIMA analyzer and laboratory-based CD4 enumeration, comparable to levels in nonpregnant HIV-infected adults. The reliability of the PIMA did not vary with gestation despite the hemodilution of pregnancy. POC CD4 technologies may be used to identify ART-eligible women in prevention of mother-to-child transmission of HIV settings to help promote the rapid initiation of ART.