engleski

Control sample analytes stability at room temperature in the light and in the dark

Introduction: Manufacturer declares the stability of control sample in refrigerator at 2 - 8 °C, while stability on room temperature is not described. Often during routine work, control sample stays longer at room temperature and it is not evident can such sample be used for analyte measurement. The aim of the study was to examine the stability of control sample during 14 hours at 1-hour time intervals at room temperature in the light and in the dark. Materials and methods: A control sample of Multichem S level 3 (Techno-path Manufacturing Ltd, Ireland) was used for analysis. Analytes were measured on the Abbott Architect c8000 analyzer (Abbott Laboratories, Abbott Park, USA): albumin, ALT, amylase, AST, total bilirubin, direct bilirubin, Ca, CK, Cl, creatinine, enzymatic creatinine, CRP, ethanol, glucose, K, lactate, LDH, lipase, phosphates, total proteins, urate and urea using Abbott’s original reagents. One aliquot of control sample was stored in a transparent tube with a stopper in the light throughout the test period, while another aliquot was stored in a dark bottle sealed in a cupboard that did not reach the light. Samples were analyzed every hour in the period from 9 am to 23 pm. For each time interval, the bias was calculated by the initial value obtained at 9 hours. Acceptance criteria for imprecision are downloaded from the Westgard Desirable Biological Variation Database web page (https://www.westgard. com/biodatabase1.htm#1). Results: Stability of all tested analytes in darkness has fully met the eligibility criteria throughout the entire test interval. Stability in the light did not satisfy calcium after the third hour of testing interval. The deviation was 2.5% and the permitted criteria was 1.05%. Conclusion: All analytes are stable for 14 hours in light and dark, except for calcium which is stable 3 hours in the light.

control sample ; analyte stability ; preanalytical phase

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