Preanalytical variables and their potential impact on biomarkers and precision medicine initiative

Errors in the preanalytical phase, spanning activities from ordering a test to presenting a sample for analysis, were reported to constitute the majority of clinical lab errors; however, the issue is still undermined, especially, in clinical trials. Patient preparation does not only include deprivation of food or, even, alcohol intake for a certain period of time, but noncaloric beverages, smoking, and exercise can make big differences in lab results. Type of blood collection tube, level of filling, way and magnitude of mixing, size of the needle, amount of pressure, and length of time for tourniquet application, capillary versus venous blood collected by a syringe or from intravenous line, plasma versus serum all can be significant preanalytical variables. Tumor acquisition with the length of warm and cold ischemia, preservation and embedding into paraffin can alter tissue quality and biomarker results remarkably. Unless properly controlled, specimen processing, handling, storage, and transportation can induce a lot of errors. Unfortunately, these variables can be exaggerated in clinical trials where samples are, mostly, dealt with busy staff with limited or no lab experience.