Table 2.
Median copeptin concentrations of all three patients’ cohorts at any measured timepoint using the three different copeptin assays.
| KRYPTOR | LIA | ELISA | p-value | |
|---|---|---|---|---|
| Healthy volunteers (n = 30) | ||||
| Plasma copeptin (pmol/l) | 14.7 [8.8, 20.6] | 10.1 [7.1, 14.0] | 48.1 [35.4, 59.0] | < 0.001* |
| KRYPTOR vs LIA | 14.7 [8.8, 20.6] | 10.1 [7.1, 14.0] | – | < 0.001* |
| KRYPTOR vs ELISA | 14.7 [8.8, 20.6] | – | 48.1 [35.4, 59.0] | < 0.001* |
| LIA vs ELISA | – | 10.1 [7.1, 14.0] | 48.1 [35.4, 59.0] | < 0.001* |
| Severely ill patients (n = 40) | ||||
| Plasma copeptin (pmol/l) | 74.3 [50.5, 135.1] | 70.9 [47.8, 108.6] | 80.1 [70.2, 125.0] | 0.025* |
| KRYPTOR vs LIA | 74.3 [50.5, 135.1] | 70.9 [47.8, 108.6] | – | 0.023* |
| KRYPTOR vs ELISA | 74.3 [50.5, 135.1] | – | 80.1 [70.2, 125.0] | 1 |
| LIA vs ELISA | – | 70.9 [47.8, 108.6] | 80.1 [70.2, 125.0] | 0.71 |
| Polyuria-polydipsia patients (n = 80) | ||||
| Plasma copeptin (pmol/l) | 2.9 [1.6, 10.3] | 2.8 [0.7, 9.7] | 17.9 [11.3, 28.9] | < 0.001* |
| KRYPTOR vs LIA | 2.9 [1.6, 10.3] | 2.8 [0.7, 9.7] | 0.70 | |
| KRYPTOR vs ELISA | 2.9 [1.6, 10.3] | 17.9 [11.3, 28.9] | < 0.001* | |
| LIA vs ELISA | 2.8 [0.7, 9.7] | 17.9 [11.3, 28.9] | < 0.001* | |
Copeptin was measured in duplicates with the KRYPTOR, the LIA and the ELISA. Continuous variables are expressed as median [interquartile range]. Three-group comparison was done using the Friedman Test. Posthoc two group comparison was done using the paired Wilcoxon Sign Rank Test with Bonferroni p-value adjustment.
*Statistically significant.