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Introduction: The aim of this study was to establish reference intervals for plasma cystatin C and creatinine in adults using the Gentians cystatin C method traceable to the international calibrator standard ERM-DA471/IFCC and a creatinine method traceable to the IDMS (Isotope Dilution Mass Spectrometry) creatinine reference method., Methods: Blood samples were collected from 304 healthy blood donors (152 men and 152 women between 17 and 66 years old) with 30-31 men and 30-31 women in each ten-year interval. Plasma cystatin C was analyzed using the Gentian Cystatin C assay on a Roche cobas c702 analyzer, and plasma creatinine was analyzed using the CREA Plus assay on the Roche Modular P analyzer., Results: The nonparametric reference intervals for plasma cystatin C were 0.58-1.00 mg/L in women (median 0.78 mg/L, range 0.56-1.06 mg/L) and 0.62-1.04 mg/L in men (median 0.79 mg/L, range 0.61-1.07 mg/L). The Mann-Whitney U test revealed no gender-related difference in plasma cystatin C (P = .21). A common reference interval in women and men was calculated to be 0.61-1.01 mg/L (median 0.79 mg/L, range 0.56-1.07 mg/L). The nonparametric reference interval for plasma creatinine was 52-89 μmol/L in women (median 69 μmol/L, range 52-92 μmol/L) and 61-108 μmol/L in men (median 86 μmol/L, range 56-118 μmol/L). The Mann-Whitney U test revealed a gender-related difference in plasma creatinine (P < .0001)., Conclusion: In conclusion, we have established reference intervals for plasma cystatin C and creatinine in adults using methods traceable to international standards., (© 2018 Wiley Periodicals, Inc.)

Backgroud: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method., Methods: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme-linked immunosorbent assay (ELISA) in a 40-sample dilution series and 39 intensive care unit (ICU) patients. Agreement was assessed with Bland-Altman's method., Results: In the ICU patients, the median HA concentration was 159.0 ng/ml (interquartile range (IQR) 117.5-362.5 ng/ml) with ELISA and 157.5 ng/ml (IQR 92.5-359.6 ng/ml) with PETIA. The mean difference was 12.88 ng/ml (95% CI, -4.3 to 30.1 ng/ml, P = 0.14) and the 95% limits of agreement were -91.17 to 116.9 ng/ml. In the dilution series, the mean difference was -59.26 ng/ml (95% CI, -74.68 to 43.84 ng/ml, P < 0.0001) and the 95% limits of agreement were 35.23 to -153.8 ng/ml., Conclusion: We found random variation between the PETIA and ELISA test that could affect performance in a clinical context, but only to a lesser extent in a research context. The new clinical biochemistry assay for HA determination will allow for large studies of the clinical utility of HA., (© 2015 Wiley Periodicals, Inc.)