Naslov
Urinary free cortisol – estimating the upper reference limit in Croatian population on the Abbott Architect i2000

Autori
Zec, Ivana ; Bokulić, Adriana ; Kruljac, Ivan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Reference intervals and decision limits / - : Clinical Chemistry and Laboratory Medicine (CCLM), 2021, S751-s751

Skup
EuroMedLab Munich 2021 – Munich

Mjesto i datum
München, Njemačka, 28.11.2021. - 02.12.2021

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
UFC, reference range

Sažetak
BACKGROUND-AIM Urinary free cortisol in the 24-hour urine sample (UFC) is one of the three initial tests for evaluating hypercortisolism.Setting up the accurate upper reference limit (URL) for UFC is essential for the diagnosis of Cushing syndrome (CS).Liquid chromatography mass spectrometry/mass spectrometry (LC-MS/MS) is considered the most accurate method to determine the UFC. Despite the limitations, immunoassays are still common methods for UFC measurement.Abbott Architect i2000 immunoassay is comparable to the LC-MS/MS method with a slight overestimation of UFC concentration. According to the manufacturer, the 95% reference interval (RI) is derived from apparently healthy individuals, ranging from 12 to 486 nmol/24h. This study aimed to calculate 95% URL for the Croatian population. METHODS Samples are collected from 234 apparently healthy individuals, 116 women and 118 men. Participants with a known disease of the hypothalamic-pituitary-adrenal axis, renal diseases, glucocorticoid administration and acute illness are excluded from the analysis. After collection, 24-hour urine samples are centrifuged and cortisol is analysed on Abbott Architect i2000. The URL is estimated with the nonparametric method as right-sided, 95% RI with the calculation of 90% confidence interval (90%CI). The extreme values are tested with the Tukey method. Summary statistics are presented as median and IQR. RESULTS Median age of all subjects is 50 (33 – 65) years. Median volume of 24-hour urine is 1825 (1300 – 2300) mL. The calculated URL is 245 nmol/24h (90%CI: 214-269 nmol/24h). UFC concentrations for nine participants are recognized as outliers by Tukey method, but still included in the calculation. Median of UFC in men and women is 110 nmol/24h and 90nmol/24h, respectively. CONCLUSIONS The estimated URL in the Croatian population is significantly lower than the upper limit of reference interval declared by the manufacturer (245 nmol/24h vs 486 nmol/24h). However, the URL refers to healthy subjects, thus cannot be mistaken for the cut off value for the diagnosis of CS.

Izvorni jezik
Engleski

Znanstvena područja
Javno zdravstvo i zdravstvena zaštita

POVEZANOST RADA