IntroductionAlthough serum-providing blood tubes with a barrier are still widely used due to their significant advantages, the use of blood tubes with a barrier to provide plasma is becoming widespread. We compared 22 analytes in a BD Vacutainer® Barricor LH Plasma tube for local clinical validation of this new lithium heparin tube with a barrier.Materials and methodsSamples from 44 volunteers were collected in different tubes (Becton Dickinson and Company): Z tube without additive (reference), clot-activator tube with gel (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with barrier (Barricor). Analyte concentrations in different tubes were compared with the reference tube. All tubes were also evaluated according to additional testing (different centrifugation durations, blood-sampling techniques and individual differences).ResultsAspartate aminotransferase (AST), glucose (Glc), potassium (K), lactate dehydrogenase (LD), sodium (Na), and total protein (TP) had a significant bias in Barricor (9.19%, - 3.24%, - 4.88%, 21.60%, - 0.40%, 5.03%, respectively) relative to the reference tube. There was no statistical difference between different centrifugation durations and individual differences for AST, K and LD in LiH and/or Barricor (P > 0.05). There was a significant bias for LD between LiH and Barricor in terms of blood-sampling techniques (21.2% and 12.4%, respectively).ConclusionsRecently, the use of plasma has become prominent due to some of its advantages. In this study, plasma AST, K, LD, Glc and TP levels in Barricor were clinically different in comparison to serum. The results of additional tests showed that higher levels of LD in Barricor did not result from haemolysis, and they might be related to other factors including number of platelets, cellular fragility, or functional environment.

Understanding and managing biotin interference in immunoassays Objectives: Biotin is a water-soluble vitamin that is an essential coenzyme in the transfer of carboxyl groups by several carboxylases involved in the synthesis of fatty acids, gluconeogenesis, amino acid metabolism, and the citric acid cycle. In the last decade or so, several reports have highlighted biotin interference causing clinically incompatible immunoassay test results. The underlying reason for this relatively new issue of biotin interference is thought to be related to the widespread use of high-dose biotin, which has led to the potential for biotin interference in routine immunoassays that use a biotin-streptavidin interaction. In November 2017 and November 2019, the US Food and Drug Administration warned the public, healthcare providers, laboratory personnel, and kit manufacturers about biotin interference and its importance. Awareness of biotin interference among laboratory staff and clinicians can prevent misdiagnosis and inappropriate treatment. The vulnerability of an immunoassay test to biotin interference is not constant; the test results may be incorrectly high or low, depending on the assay technology. Biotin can be a challenging source of interference and analytic error in terms of detection and prevention. Laboratory staff should be informed about this potential interference in immunoassays using biotin-streptavidin linkage. To reduce the likelihood of erroneous results, particular attention must be given to the test results of certain patients (e.g., patients with multiple sclerosis) or those that are not compatible with the clinical findings. To mitigate this patient safety risk, laboratories using methods vulnerable to biotin interference should develop appropriate solutions to detect and overcome biotin interference.