Assessment of Biochemical Analytes Stability: The Role of Centrifugation and Storage Conditions in the Preanalytical Phase

The preanalytical phase represents a critical component of laboratory testing, encompassing all procedures prior to sample analysis and exerting a substantial influence on the quality and reliability of laboratory results. To evaluate changes in the concentrations of commonly measured biochemical analytes in blood samples subjected to different preanalytical conditions, including centrifugation duration, storage temperature and storage time. Blood samples obtained from 20 individuals (960 measurements) were analysed for glucose, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), high‐density lipoprotein (HDL), low‐density lipoprotein (LDL), triglycerides (TG), potassium (K), sodium (Na) and chloride (Cl). Samples were centrifuged for 5, 10 and 15 min, analysed under optimal conditions (within 2 h of collection), and subsequently reassessed after storage for 2, 4, 8, 10 and 14 days at +23, 4 and −20°C. Statistical analysis was performed using the Kruskal–Wallis test. Storage temperature significantly affected HDL, TG, ALT, AST, glucose, albumin, LDL, and TC ( p < 0.001) concentrations, with higher HDL and TG concentrations at +23°C ([1.71(1.12‐2.50)]mmol/l] and [1.82(0.73‐10.19)]mmol/l respectively) and significant AST and ALT concentration decrease at 23°C ([16.0 (4‐60)]U/l and [10.0(2‐95)]U/l respectively). Storage duration influenced TC, HDL, TG, albumin, ALT, and AST concentrations ( p < 0.001). Centrifugation time had a significant effect only on serum chloride and glucose concentrations ( p = 0.018, p = 0.025 respectively). Most biochemical analytes were significantly influenced by storage temperature and duration, whereas centrifugation time had a comparatively limited effect.