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. Author manuscript; available in PMC: 2022 Nov 1.
Published in final edited form as: J Immunol Methods. 2021 Aug 28;498:113132. doi: 10.1016/j.jim.2021.113132

Table 2A.

Performance characteristics of total RNA isolated from the filtrates stored either at −80°C or Ambient (Room) Temperature.

S.no Time to process (days) Volume (cc)a A260/280 Ratiob Nanodrop based total RNA (μg)c Qubit based total RNA (μg)d 18S rRNA copies/μg RNAe TGFβ1 copies/μg RNAe hsa-miR-26a copies/μg RNAe
−80°C RT −80°C RT −80°C RT −80°C RT −80°C RT −80°C RT
1 4 37.5 1.84 1.79 0.96 0.93 0.74 0.74 8.65E+09 6.50E+09 4.64E+04 1.99E+04 1.43E+06 1.69E+06
2 4 47.5 1.99 1.99 0.23 0.25 0.23 0.18 8.18E+08 1.13E+09 9.11E+03 5.38E+03 8.47E+05 9.36E+05
3 4 45 1.64 1.71 0.27 0.32 0.19 0.15 5.08E+08 8.31E+08 4.76E+03 3.44E+03 1.35E+06 8.51E+05
4 2 45 1.89 1.92 1.41 1.53 0.99 1.29 1.66E+10 2.01E+10 6.08E+04 4.88E+04 2.25E+06 3.04E+06
5 2 30 1.40 1.66 0.20 0.26 0.14 0.17 2.10E+08 7.70E+08 1.65E+02 3.62E+02 6.40E+05 4.31E+05
6 2 35 1.97 1.81 0.64 0.69 0.52 0.58 1.04E+09 2.33E+08 9.77E+02 1.67E+02 6.67E+05 6.02E+05
7 4 17.5 1.92 1.98 2.26 2.54 0.25 0.29 8.04E+08 1.75E+09 6.21E+03 2.12E+03 2.72E+06 2.07E+06
8f 4 22.5 2.01 0.92 0.05 0.04 n/a n/a n/a n/a n/a n/a n/a n/a
9 4 45 1.72 1.57 0.16 0.13 0.10 0.10 2.65E+08 1.94E+08 2.15E+03 4.64E+02 5.47E+05 8.34E+05
10 2 55 1.75 1.80 0.59 0.63 0.11 0.11 1.99E+09 2.46E+09 6.57E+03 8.11E+03 9.17E+05 7.85E+05
11 2 37.5 1.94 1.94 4.64 5.17 0.94 0.92 9.17E+08 1.14E+09 4.40E+03 4.02E+03 7.35E+05 6.08E+05
12 2 50 1.69 1.54 0.26 0.24 0.15 0.20 3.04E+08 5.86E+08 5.40E+02 2.52E+03 1.14E+06 7.96E+05
Median 41 1.87 1.80 0.43 0.48 0.23 0.20 8.18E+08 1.13E+09 4.76E+03 3.44E+03 9.17E+05 8.34E+05
25th Percentile 31 1.70 1.59 0.21 0.24 0.14 0.15 3.04E+08 5.86E+08 9.77E+02 4.64E+02 6.67E+05 6.08E+05
75th Percentile 47 1.96 1.94 1.30 1.38 0.74 0.74 1.99E+09 2.46E+09 9.11E+03 8.11E+03 1.43E+06 1.69E+06
Wilcoxon P value g 0.57 0.04 0.30 0.24 0.08 0.58

Urine samples from 12 kidney allograft recipients were processed using the ZR Urine RNA Isolation Kit™. One urine sample did not yield sufficient RNA for reverse transcription and was excluded from downstream analysis. The RNA containing filtrate were stored either at −80°C or at ambient temperature for 2 or 4 days prior to RNA isolation using Zymo-Spin™ IC Columns.

a

The volume of urine processed using the ZR Urine RNA Isolation Kit™.

b

A260/280 ratio was measured using the NanoDrop® ND-1000 spectrophotometer.

c

The amount of RNA measured using the NanoDrop® ND-1000 spectrophotometer.

d

The amount of total RNA measured using the Qubit fluorometer.

e

Absolute copy number of 18S rRNA, TGF-β1 mRNA, and hsa-miR-26a miRNA were measured with customized RT-qPCR assays using gene specific oligonucleotide pairs and TaqMan probes on 7500 Fast Real-Time PCR System (Applied Biosystems).

f

Total RNA yield from urine sample 8 was below detection limit for measurement using the Qubit Fluorometer and RNA was insufficient for reverse transcription to cDNA and measurement of 18S rRNA, TGF-β1 mRNA and miR-26a.

g

P values derived using Wilcoxon matched pairs signed-ranks test.