Evaluation of the Cavidi Exavir load reverse transcriptase assay (version 3.0) for HIV viral load against the Roche Amplicor Monitor (version 1.5) for use in monitoring viral load in patients infected with the HIV -1 virus.

Abstract

Title: Evaluation of the Cavidi ExaVir load Reverse Transcriptase Assay (version 3.0) for HIV Viral Load against the Roche Amplicor Monitor (version 1.5) for use in monitoring viral load in patients infected with the HIV virus. Introduction. There are two types of HIV, HIV-1 and HIV-2 and both types are known to cause AIDS, although infection with HIV-1 is more common worldwide. The concentration of HIV RNA in plasma is a critical marker for predicting disease progression and for monitoring the efficacy of antiretroviral drug therapy. However, most viral load assays are not readily available in Zimbabwe due to the complexity and the need for nucleic acid amplification hence the need to explore other available alternatives. The objective of this study was to evaluate the Cavidi ExaVir load Reverse transcription Assay Version 3.0 for quantifying HIV-1 viral load using the Roche Amplicor monitor version 1.5 as the gold standard. Method This was a cross sectional comparative study of two kits where 21 whole blood samples being submitted for viral load testing at Flow cytometry centre were centrifuged and separated within 2 hours of collection and then stored for batched testing with 2 aliquots per sample. The samples were then thawed for testing using the Cavidi Exavir load v 3.0 at flow cytometry centre. The second aliquot was tested using the Roche Amplicor Monitor v1.5 at UZ-UCSF laboratory. The results were then correlated using STATA biostatistics software. Results: There was a very strong linear correlation in viral load measurement between the Cavidi Exavir Load v 3.0 and the Roche Amplicor Monitor v 1.5 ( r=0.94 and p < 0.05). 85.7% of the samples showed an agreement of 0.68 log 10 between the two methods (fivefold) which is equal to the total variation that can be expected in viral load measurements. Conclusion: The Cavidi Exavir load v 3.0 correlates strongly with the Roche Amplicor monitor v 1.5 in measuring plasma viral load concentrations and can be used to monitor viral load in clinical specimens.