Pitfalls with rapid HIV antibody testing in HIV-infected children in the Western Cape, South Africa.
BACKGROUND
Rapid HIV antibody tests are commonly used for HIV diagnosis in the developing world. These tests are generally reported as sensitive, despite paucity of evaluations in paediatric populations.


OBJECTIVE
We tested specimens of paediatric patients, known to be HIV-infected, to detect any false negative tests and determine associations with such an outcome.


METHODS
One hundred and fifty-three specimens, from 109 patients, recorded to be HIV-infected by standard testing, were tested on the Capillustrade mark HIV-1/HIV-2 test (Trinity Biotech, Ireland); 150 specimens also had sufficient volume to be tested on Abbott Determinetrade mark HIV1/2 assay (Abbott GmbH, Wiesbaden, Germany). Treatment information, CD4 counts and HIV-1 viral load measurements were obtained from patient files and laboratory databases.


RESULTS
Twenty-one of 153 specimens tested negative on the Capillus (sensitivity 86.3%). False negative results by Capillus were associated with antiretroviral treatment (ART) (p=0.0018) and lower HIV-1 viral load (p=0.013). Serial dilutions of some of the specimens indicated that both rapid tests, and the Capillus in particular, became negative at lower dilutions than an HIV enzyme immunoassay (EIA).


CONCLUSIONS
The Capillus test had an unexpectedly low sensitivity in a South African population of HIV-infected children that had access to antiretroviral treatment, posing a risk of false negative HIV testing.
Claassen
M
M
Discipline of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Stellenbosch and NHLS, Tygerberg 7505, South Africa.
van Zyl
G U
GU
Korsman
S N J
SN
Smit
L
L
Cotton
M F
MF
Preiser
W
W
D015492:AIDS Serodiagnosis; D019380:Anti-HIV Agents / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count; D005188:False Negative Reactions; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013019:South Africa; D013223:Statistics as Topic; D019562:Viral Load
D019380:Anti-HIV Agents; D015483:HIV Antibodies