Special issue: Responsible writing in science Original articles Introduction Because laboratory testing has a serious impact on clinical decision making the main task of laborato- ry professionals is to ensure high quality of test re- sults. Implementation of high-quality test tubes can assure reliable test results and optimize labo- ratory work-fow through reducing the need for blood specimen re-collection as well as shorten- ing time needed for sample preparation. Introduc- ing new test tubes into routine application re- quires their prior verifcation (1). The procedure is well defned in Clinical and Laboratory Standards Institute (CLSI) guideline GP-34A (2). Electronic supplementary material available online for this article. Abstract Introduction: The aim was to evaluate the BD Barricor tubes by comparison with the BD Rapid Serum Tubes (RST) through measuring 25 analytes and monitoring sample stability after 24 hours and 7 days. Materials and methods: Samples of 52 patients from diferent hospital departments were examined. Blood was collected in BD RST and BD Barricor tubes (Becton, Dickinson and Company, Franklin Lakes, USA). Analytes were measured by Beckman Coulter AU 480 (Beckman Coulter, Brea, USA), Dimension EXL (Siemens Healthcare Diagnostics, Newark, USA) and ARCHITECT i2000SR (Abbott Diagnostics, Lake Forest, USA). Between-tube comparison for each analyte was performed, along with testing analyte stability after storing samples at 4 °C. Results: BD Barricor tubes showed unacceptable bias compared to BD RST tubes for potassium (K) (- 4.5%) and total protein (4.4%). Analyte stability after 24 hours was acceptable in both tested tubes for most of analytes, except for glucose, aspartate aminotransferase (AST) and lactate dehydro- genase (LD) in BD Barricor and free triiodothyronine in BD RST sample tubes. Analyte stability after 7 days was unacceptable for sodium, K, calcium, creatine kinase isoenzyme MB, AST, LD and troponin I in both samples; additionally for glucose, alkaline phosphatase and albumin in BD Barricor. Conclusion: All analytes, except K and total protein, can be measured interchangeably in BD RST and BD Barricor tubes, applying the same reference intervals. For most of the analytes, sample re-analysis can be performed in both tubes after 24 hours and 7 days, although BD RST tubes show better 7-day analytes stability over BD Barricor tubes. Keywords: BD Barricor tube; stability; serum; plasma; evaluation Submitted: March 11, 2020 Accepted: July 08, 2020 Test results comparison and sample stability study: is the BD Barricor tube a suitable replacement for the BD RST tube? Sanja Mandić * 1,2 , Dario Mandić 1,2 , Iva Lukić 1,2 , Tara Rolić 1,2 , Vesna Horvat 1,2 , Maja Lukić 1 , Silvija Osvald 1 , Vatroslav Šerić 1,2 1 Institute of Clinical Laboratory Diagnostics, Osijek University Hospital, Osijek, Croatia 2 Department of Chemistry, Biochemistry and Clinical Chemistry, Faculty of Medicine, University of Osijek, Osijek, Croatia *Corresponding author: mandic.sanja@gmail.com https://doi.org/10.11613/BM.2020.030704 Biochem Med (Zagreb) 2020;30(3):030704 1 For a long-time serum was considered the stand- ard sample for analysis in clinical chemistry (3). In recent years plasma has become the preferable sample, especially for emergency laboratory ana- lytes, because of time-saving advantages and low- er risk of haemolysis (3-5). BD Rapid Serum Tubes (RST) (Becton, Dickinson and Company, Franklin Lakes, USA) are vacuum tubes containing a thrombin-based clot activator and polymer gel which provides rapid serum sep- aration and makes them suitable for emergency