EXPRESS: Evaluation of the quick-clotting serum separator tube, VQ-TubeTM, for clinical chemistry and thyroid hormone assays

Background: The type of blood collection tube affects specimen quality and laboratory results. Because plasma specimens have a shorter processing time compared to serum specimens, emergency biochemistry tests use plasma. However, serum specimens remain stable after centrifugation and show more accurate results than plasma. Therefore, a quick-clotting serum separator tube (SST) is expected to be useful for shorter turnaround times and accurate results. We evaluated a new quick-clotting SST VQ-Tube^TM (AB Medical, Korea) for clinical chemistry and thyroid hormone assays. Methods: One hundred volunteers from four university hospitals were recruited and peripheral blood samples were collected in quick-clotting SST VQ-Tubes^TM and the commonly used SST V-Tubes^TM. The obtained specimens were used for 16 clinical chemistry assays and three thyroid hormone assays. Results: The differences (%) in the test results obtained from the samples in each tube satisfied the allowable difference ranges (19 assays). The differences in the test results between the tubes satisfied the desired specifications for accuracy except for the glucose results (2.75%). The paired t-test revealed significant differences between the results of six assays but each set of results showed a good correlation. Samples were visually inspected for serum clarity and gel barrier integrity, and incomplete clotting reactions and hemolyzed serum were not observed. Conclusion: The new quick-clotting VQ-Tube^TM demonstrated reliable test results compared to the commonly used SST V-Tube^TM. This quick-clotting tube will provide fast test results with adequately separated serum specimens, especially for patients who need fast tests.

The Interaction of the Gut Microbiota with the Mucus Barrier in Health and Disease in Human

Glycoproteins are major players in the mucus protective barrier in the gastrointestinal and other mucosal surfaces. In particular the mucus glycoproteins, or mucins, are responsible for the protective gel barrier. They are characterized by their high carbohydrate content, present in their variable number, tandem repeat domains. Throughout evolution the mucins have been maintained as integral components of the mucosal barrier, emphasizing their essential biological status. The glycosylation of the mucins is achieved through a series of biosynthetic pathways processes, which generate the wide range of glycans found in these molecules. Thus mucins are decorated with molecules having information in the form of a glycocode. The enteric microbiota interacts with the mucosal mucus barrier in a variety of ways in order to fulfill its many normal processes. How bacteria read the glycocode and link to normal and pathological processes is outlined in the review.

Long-term stability of glucose: glycolysis inhibitor vs. gel barrier tubes

Background:Measuring the glucose concentration in whole blood samples is critical due to unsatisfactory glycolysis inhibition. Previous studies showed that Terumo tubes were superior, but they were taken off the European market in 2016 and alternatives were required. This initiated the present evaluation of glucose stability in five available tube types.Methods:Venous blood samples were collected from 61 healthy volunteers to test tubes supplied by Terumo (two sets), Greiner FC-Mix, BD FX-Mixture and BD serum. After sampling, the contents were thoroughly mixed and centrifuged within an hour. The glucose concentrations were determined and the samples resuspended except for BD serum tubes (gel barrier). The first 30 samples were stored at room temperature and the remaining 31 at 4°C. After 24, 48, 72 and 96 h, all tubes were (re)centrifuged, and glucose concentration measurements were repeated.Results:Changes in glucose concentrations over time differed significantly between the investigated tube types and to a certain extent between the two storing conditions. Glycolysis was most evident in the BD FX-mixture tubes. Good glucose stability was observed in samples retrieved form BD serum and Greiner tubes. The stability in both Terumo tubes was comparable to that in other studies. Although Greiner and both Terumo tubes are supposed to contain the same glycolysis inhibitor, glucose stability differed between these tubes.Conclusions:We showed that Greiner is an acceptable alternative to Terumo and that glucose in serum that was rapidly separated from corpuscles by a gel barrier is stable for an extended time.