Additionally, we calculated receiver operating characteristics to assess the diagnostic capability of the DIG, MAN, and HYD for identifying high urine concentration (USG ≥1.020) based on the area under the curve (AUC) and sensitivity and specificity. 05 indicated significance for both analyses. The Bland-Altman analysis was used to determine mean estimation bias, direction, and 95% limits of agreement among refractometers with HYD as the standard. Spearman correlations (including 95% CIs based on the Fisher Z transformation) were conducted to determine the relationships between reference measurements (☋x) or the selected standard (DIG). As the HYD data were not distributed normally, we calculated the mean differences for all outcomes at different temperatures using Mann-Whitney U tests. We performed separate analyses between all tools for the 2 experiments.
We either measured all samples in duplicate and used the average for analysis when the measurements were not more than 0.005 apart or we measured the samples in triplicate, used the median for analysis when the difference between the first 2 measurements >0.005, and used the average of the 2 measurements for analysis. Before use, we calibrated both refractometers and the HYD using distilled water at 20☌. Each urine sample was measured at 3 temperatures on the same day within an 8-hour period. During experiment 2, we used a warm-water bath at 20 ± 1☌ and 37 ± 1☌ and a Traceable Long-Stem Digital ULTRA thermometer with a resolution of 0.1☌ and accuracy of ☐.2☌.
During experiment 1, we used an oven (model Heratherm OGS100 Thermo Fisher Scientific) and a Traceable Sentry Thermometer (Thermo Fisher Scientific) with a resolution of 1☌ and accuracy of ☑☌ to measure sample temperature. Measurements for both experiments were obtained in the following order: samples were cooled in the refrigerator (5☌) and then the closed samples were heated to 20☌ and to 37☌. For both experiments, the samples were prepared separately for measurement with the refractometers (2 × 15 mL in 45-mL transparent plastic freestanding centrifuge tubes Evergreen Scientifics) and HYD (1 × 45 mL in glass Erlenmeyer flasks Thermo Fisher Scientific).
0 kommentar(er)
