Sensitivity and specificity of Amplicor HIV-1 DNA Test, version 1.5 and Cobas
AmpliPrep/Cobas TaqMan PCR methods for the diagnosis of HIV among HIV exposed infants in
selected health facilities, western Kenya.
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Authors: Makwaga Olipher , Muigai AW , Andayi F , Mokaya T , Matilu M
1. Center for Infectious and Parasitic Diseases Control Research - KEMRI. P. O. Box 3-50400,
Busia, Kenya. 2. Jomo Kenyatta University of Agriculture and Technology P.O. B OX 6200000200 Nairobi, Kenya
Introduction: In Kenya, both Amplicor HIV-1 DNA Test, version 1.5 and Cobas
AmpliPrep/Cobas TaqMan PCR methods have been adopted in the diagnosis of infants of 18
months and below. However, minimal data has been documented regarding their Sensitivities
and specificities in the diagnosis of these infants.
Objective: This study determined the sensitivities and specificities of the above mentioned
diagnostic methods in the diagnosis of infants born to HIV infected mothers.
Methodology: This was a cross-sectional study involving 717 dried blood spot samples collected
between 2010 to 2012 from 18 months and below infants. These samples were analyzed at
KEMRI-CIPDCR using two PCR methods. The sensitivities and specificities of the total number
of infants were determined. Similarly, the infants were grouped into two groups (≤ 6months and
> 6 months according to WHO) and their sensitivities and specificities of the two methods were
also determined.
Results:
Sensitivities and specificities of Amplicor HIV-1 DNA Test, version 1.5 were as follows: all infants,
91.3%; 98.1%, ≤6months, 96.3%; 94.4%, >6months, 84.2%; 94.0% respectively. For Cobas
AmpliPrep/Cobas TaqMan PCR: all infants, 76.4%; 99.4%, ≤6months, 96.3%; 94.4%, > 6months, 57.1%;
98.4.0% respectively.
Discussion/Conclusion/recommendation: The Sensitivities of the two PCR methods among all
the infants and >6months was lower for Cobas PCR than Amplicor. However, the sensitivity for
both methods among infants of ≤6months was same. All the specificities between both PCR
methods were similar. Therefore, either of the method should be used to diagnose HIV among
infants who are ≤6 months of age born to HIV infected mothers. However, there is need for more
studies to elucidate the difference in sensitivites among infants of > 6 months of age.