Table 1.
Breakdown of study sample characteristics.
Fig 1.
The proportion of samples in EDTA or PPT tubes with repeat viral load within -0.5 to +0.5 log copies per mL of the first test for each storage category.
In 78–100% of PPT samples and 74–90% of EDTA samples the repeat viral load was within +/- 0.5 log copies/mL.
Fig 2.
Box and whisker plots of log viral load change (test 2-test 1) in EDTA and PPT samples at 4°C, 20°C and 30°C: All samples with detectable viral load >19 copies per ml in test 1 were analysed.
Median and IQR for each temperature/storage category is given. Plus and minus 0.5log viral load change indicated by solid red lines.
Fig 3.
Repeat viral load results of samples that were undetectable in test 1: The proportion of samples that were undetectable or <20 copies/mL, 20–100 copies/mL, 100–500 copies/mL, 500–1000 copies/mL or >1000 copies/mL on repeat testing are shown.
In (a) samples that were stored at 4°C for 72, 96 and 168 hours, (b) samples that were stored at 20°C and (c) samples that were stored at 30°C.
Fig 4.
Omitting centrifugation immediately prior to repeat testing is associated with a higher viral load in the second test: In (a), the log value for each sample in test 1 (X-axis) is plotted against the log value in test 2 (Y-axis). Line indicates an ideal regression line, r2 = 1. In (b) the repeat results of samples that were undetectable (LDL) in test 1 are graphed according to the following categories: undetectable or <20 copies/mL, 20–100 copies/mL, 101–500 copies/mL, 501–1000 copies/mL or >1000 copies/mL.