Table 1.
Comparison of mean IL-6 concentrations between different tube types stored at different temperatures. Concentrations of IL-6 are not significantly different between room temperature (RT) and 4°C incubated K2EDTA tubes at any time period; however, there is a significant increase in IL-6 in RT incubated P100 tubes compared with 4°C tubes over time (Panel A; significant differences are marked in bold). At 4°C, concentrations of IL-6 do not differ significantly between K2EDTA and P100 tubes (Panel B).
| PANEL A | PANEL B | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| IL-6 | K2EDTA | P100 | 4°C | |||||||
| Comparison | 4 hrs incubation, RT vs 4°C | 24 hrs incubation, RT vs 4°C | 48 hrs incubation, RT vs 4°C | 4 hrs incubation, RT vs 4°C | 24 hrs incubation, RT vs 4°C | 48 hrs incubation, RT vs 4°C | baseline, K2EDTA vs P100 | 4 hrs incubation, K2EDTA vs P100 | 24 hrs incubation, K2EDTA vs P100 | 48 hrs incubation, K2EDTA vs P100 |
| Mean fold change (SEM) | 0.98 (0.02) | 1.04 (0.03) | 1.01 (0.04) | 0.85 (0.05) | 4.70 (0.72) | 15.18 (1.94) | 0.99 (0.05) | 0.95 (0.04) | 0.95 (0.04) | 0.91 (0.05) |
| Mean difference (SEM) | −0.02 (0.02) | 0.03 (0.03) | 0.00 (0.04) | −0.17 (0.08) | 3.44 (1.08) | 11.72 (2.16) | 0.00 (0.03) | −0.04 (0.04) | −0.03 (0.02) | −0.06 (0.04) |
| 95% CI of difference (lower, upper) | −0.06, 0.03 | −0.07, 0.13 | −0.10, 0.10 | −0.36, 0.03 | 0.66, 6.21 | 6.17, 17.23 | −0.09, 0.08 | −0.15, 0.07 | −0.09, 0.02 | −0.18, 0.05 |
| Paired t (df) | −0.98 (4) | 0.96 (3) | 0.70 (4) | −2.22 (5) | 3.18 (5) | 5.42 (5) | −0.06 (5) | −1.08 (4) | −1.67 (4) | −1.50 (4) |
| P | 0.38 | 0.41 | 0.95 | 0.08 | 0.03 | <0.01 | 0.96 | 0.34 | 0.17 | 0.21 |