Fig 1.
Overview of collection and management of urine samples to evaluate optimal EDTA concentration and storage temperature.
This evaluation was performed in a set of urine samples from five volunteer women, who collected a first-morning, first-void urine sample, in six different cups (25ml each). Cups contained different EDTA concentrations added prior to urine addition: No EDTA, 10mM and 40mM EDTA. Half of the samples (the ones labeled with odd numbers) were stored at room temperature and those with even numbers were stored in the fridge at ~4°C. DNA extraction and quantification were performed 24 hours after collection.
Fig 2.
Overview of urine sample collection and processing of second evaluation.
Separating samples into two groups with different EDTA concentrations, further divided to examine different lengths of time from urine specimen collection to time of specimen processing. This evaluation was performed as a set of urine samples from five volunteer women, who collected a first-morning, first-void urine sample, in six different cups (25ml each). Three cups contained 10mM EDTA while the other three cups contained 40mM. Samples were then processed at 24, 48 and 72 hours as shown.
Fig 3.
Overview of sample collection and processing for the third evaluation.
Two samples were collected from each of the five participants, one from a first-morning micturition and a second one at a convenient time of the day which differed between women and was not prespecified. Samples were then stored at room temperature until DNA extraction 24 hours after collection.
Fig 4.
DNA concentration in samples stored in different EDTA concentrations and temperatures.
The top of the box represents the upper quartile (p75), the bottom the lower quartile (p25), and the x-patterned line the median (p50), the median is identified above the line. The upper and lower whiskers extend to 1.5 times the interquartile range. The best DNA concentrations resulted from EDTA at 40mM, both at 25°C and 4°C. The best storage temperature was 25°C compared to 4°C, regardless of EDTA concentration. DNA extraction and quantification presented for this particular experiment were performed 24 hours after collection.
Fig 5.
DNA concentration of samples processed at different times after sample collection.
The top of the box represents the upper quartile (p75), the bottom the lower quartile (p25), and the line the median (p50), the median is displayed above the line. The upper and lower whiskers extend to 1.5 times the interquartile range, while the dots mark the largest and smallest values of the distribution.
Table 1.
Type specific HPV positivity differences between urine and cervical samples.
Table 2.
Supplies for urine self-sampling.