Effects of hemolysis interference on routine biochemistry parameters

Introduction: Hemolysis is still the most common reason for rejecting samples, while reobtaining a new sample is an important problem. The aim of this study was to investigate the effects of hemolysis in different hemolysis levels for mostly used biochemical parameters to prevent unnecessary rejecti-ons. Materials and methods: Sixteen healthy volunteers were enrolled in the study. Four hemolysis levels were constituted according to hemoglobin concentrations and they were divided into five groups: Gro-up I: 0-0.10 g/L, Group II: 0.10-0.50 g/L, Group III: 0.51-1.00 g/L, Group IV: 1.01-2.50 g/L, Group V: 2.51-4.50 g/L. Lysis was achieved by mechanical trauma. Results: Hemolysis interference affected lactate dehydrogenase (LD) and aspartate aminotransfera-se (AST) almost at undetectable hemolysis by visual inspection (plasma hemoglobin 1 g/L). Alanine aminotransferase (ALT), cholesterol, gamma glutamyltransferase (GGT), and inorganic phosphate (P) concentrations were not interfered up to severely hemolyzed levels (hemoglobin: 2.5-4.5 g/L). Albumin, alkaline phosphatase (ALP), amylase, chloride, HDL-cholesterol, creatine kinase (CK), glucose, magnesium, total protein, triglycerides, un-saturated iron binding capacity (UIBC) and uric acid differences were statistically significant, but re-mained within the CLIA limits. Conclusion: To avoid preanalytical visual inspection for hemolysis detection, improper sample rejec-tion, and/or rerun because of hemolysis, it is recommended in this study that, routine determination of plasma or serum free hemoglobin concentrations is important. For the analytes interfered with hemolysis, new samples have to be requested

Stability studies of common biochemical analytes in serum separator tubes with or without gel barrier subjected to various storage conditions

Introduction: The collected and shipped blood samples are exposed to a various extra-analytical factors prior to analysis. The aim of the study was to determine the stability of analytes in serum gel tubes and plain tubes exposed to a range of storage temperatures and times after centrifugation. Materials and methods: Fifteen healthy volunteers were recruited and venous blood was collected into four tubes, two with and two without gel separator. Analyzing the baseline samples in 30 min, all were stored at 4ºC or 24ºC for 6, 12, 18, 24, 30, 36, 48 and 72 hours and 1 week. Sixteen biochemi-cal anaytes were measured on each sample. Variations remained under the desirable bias conside-red as clinically insignificant. Results: On day three, most analytes remained stable including albumin, protein, creatinine, choles-terol, triglycerides, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminot-ransferase (ALT), creatine kinase (CK), lactate dehydrogenase (LD) regardless of tube types. Gluco-se concentration decreased markedly (P = 0.001) beginning from the first hours of storage in plain serum. The stability maximized for the analytes including glucose, total bilirubin, urea nitrogen (BUN), uric acid stored at 4 ºC in gel tubes. Aspartate aminotransferase (AST) activity increased significantly (P = 0.002) up to 48-h, however bias was not significant clinically. High density lipoprotein (HDL) con-centration was stable in gel tubes at 24 ºC, in plain tubes at 4 ºC stored up to 36-h. Conclusion: Serum gel or non-gel tubes might be used interchangeably for 11 analytes chilled or at 24 ºC, whereas some restrictions must be applied for glucose, AST, BUN, HDL, and uric acid