Figure 4.

Effect of increased plasma volume and centrifugation to concentrate SIV. Viremic plasma from SIVmac239-infected plasma was serially diluted ten-fold and volumes of 0.5 ml and 1.5 ml were subjected to centrifugation prior to vRNA extraction, cDNA synthesis and qPCR. SIV copy equivalents (Eq) per ml of each dilution were compared against the bDNA copy Eq. By linear regression, results of SIV PVL exhibited high goodness of fit (R²) values using 0.5 ml and 1.5 ml initial volumes of viremic plasma that were statistically significant. By ANCOVA, there was no significant difference in slope or intercept between linear regression values of results in serially diluted plasma and application of 0.5 ml versus 1.5 ml plasma volumes to the extraction procedure indicating that increased plasma volume and centrifugation retain qPCR output fidelity.