Objectives Urine samples are frequently used in the clinical practice. In our study, we aimed to calculate the biological variations (BV) of analytes and analyte/creatinine ratios measured in spot urine. Methods Second-morning spot urine samples were collected from 33 (16 female, 17 male) healthy volunteers once weekly for 10 weeks and analyzed in the Roche Cobas 6,000 instrument. Statistical analyzes were performed using BioVar, an online BV calculation software. The data were evaluated in terms of normality, outliers, steady state, homogeneity of the data, and BV values were obtained by analysis of variance (ANOVA). A strict protocol was established for within-subject (CVI) and between-subject (CVG) estimates for both genders. Results There was a significant difference between female/male CVI estimates of all analytes except potassium, calcium and magnesium. No difference was found in CVG estimates. When the analytes that had a significant difference in CVI estimates in spot urine analytes were compared to creatinine, it was observed that the significant difference between the genders disappeared. There was no significant difference between female/male CVI and CVG estimates in all spot urine analyte/creatinine ratios. Conclusions Since the CVI estimates of analyte/creatinine ratios are lower, it would be more reasonable to use them in result reporting. Reference ranges should be used with caution, since II values of almost all parameters are between 0.6 and 1.4. The CVI detection power of our study is 1, which is the highest value.

Aim: Diagnostic biomarkers are needed for pediatric acute appendicitis (AA). We hypothesized that presepsin (soluble CD14 subtype), a biomarker for sepsis, can also be used in pediatric AA and aimed to investigate its diagnostic value in those patients. Materials and Methods: This prospective case-control study was conducted on children admitted to the Pediatric Emergency Department with suspected acute appendicitis. Serum levels of interleukin-6, and presepsin were statistically analyzed for their diagnostic values. Results: No remarkable demographic differences were present between the 41 cases and 47 controls. Clinical and routine laboratory findings were significantly positive for acute appendicitis in the cases compared to controls. ROC analysis indicated an AUC for presepsin as 0.999 (CI 95%: 0.890-0.993) and for interleukin-6 as 0.963 (CI 95%:0.949-1.000). The best cut-off point value for presepsin was at 739 pg/ml, corresponding to a sensitivity of 97.56% and a specificity of 100%. The best cut-off point value for interleukin-6 was at 19 pg/ml, corresponding to a sensitivity of 97.56% and a specificity of 90.32%. Conclusions: Our study results indicate that presepsin can be considered a biomarker for diagnosing appendicitis in pediatric cases. Future studies might better include the combination with other biomarkers in pediatric cases.