Abstract:
Proficiency testing for Human Immunodeficiency Virus offers a platform for
institutions and individuals to assess their technical competencies. It boosts morale
and confidence among the laboratory operators and provides opportunities for
improvement among participating institutions. Post-market field validation of HIV
rapid diagnostic test is important because it increases confidence in the quality of
testing services. Moreover, it confirms that the kit prequalified by WHO, is of
superior quality (and vice versa) in terms of sensitivity and turnaround time.
However, a shortcoming in test validation is that once kits are procured, rarely does
field validation take place. As of 2008, no study in East Africa in general and
Kenya, in particular, had looked at the field validation of photogrammetric testing.
This current study is thus aimed at comparing the efficacy of serological and
photogrammetric testing for HIV screening in non-laboratory resource-limited
settings within Nairobi County. Besides, the study explores a new cost-effective
method which can complement routine proficiency testing as a training tool for fieldbased validation. A longitudinal study was conducted using three rounds of
proficiency and photogrammetric testing respectively. A total of 234 experienced and
non-experienced operators were recruited using purposive sampling. A total of 702
dried tube specimen panel samples were tested using the Determine algorithm, while
702 photos were visually interpreted. The study revealed that the validity of
serological testing was 98.07% and 96.21% for sensitivity and positive predictive
values respectively and 70.37% and 82.61% for specificity and negative predictive
values respectively. The validity of photogrammetric testing was 96.43% and
98.63% for sensitivity and positive predictive values respectively, and 70% and
46.7% for specificity and negative predictive value respectively. Lastly, the overall
accuracy was 94.5% and 95.30% for proficiency and photogrammetric testing
respectively, calculated as the percentage of true positives and true negatives on
overall results. This study concludes that Determine algorithm is still sensitive and
specific as such, it can still be used for proficiency testing of HIV panels. Besides, it
was established that photogrammetric testing could be interpreted with higher
accuracy compared to proficiency testing. The study recommendes that a higher
accuracy rate of interpretation of HIV photographed tests can be used to assess
proficiency levels of operators, while photogrammetric testing is viable as a
complementary tool for identifying and monitoring operators testing competencies in
resource-limited settings.