End-user verification results of two serum separator tubes for clinical chemistry analytes according to CLSI GP34-A and CLSI GP41-A6

Tube manufacturers use different composition of gels and blood clot activator formulations in serum tube production. Our aim was to investigate the within-tube (repeatability) and between-tube variation, concordance between comparison results of BD and VacuSEL tubes. Blood samples were collected from control subjects (n = 20) and patients (n = 30) in accordance with the CLSI GP41-A6 and CLSI GP34-A guidelines. Twenty-three clinical chemistry parameters were analysed via Roche Cobas C702 Chemistry Analyzer on T0 (0 hour) and T24 (24 hour). Mean differences % were compared with Wilcoxon matched pair test. Clinical significance was evaluated based on desirable bias according to total allowable error (TEa). VacuSEL tubes demonstrated acceptable performance for the results of 20 parameters with regards to desirable bias % limits. Lactate dehydrogenase (LD) [mean difference % (%95 confidence intervals (CI) values of BD and VacuSEL tubes at T0 [6.41% (4.80-8.01%)]; sodium (Na) and total protein (TP) at T24 [-0.27% (-0.46 to -0.07%) and -1.39% (-1.87 to -0.91), respectively] were over the desirable bias limits (LD: 4.3%, Na: 0.23% and TP: 1.36%, respectively) but not exceeding total biological variation CV % [Na: 0.5 (0.0-1.0) % and TP: 2.6 (2.3-2.7) %). %95 confidence intervals (CI) of T0 LD values overlap with within-subject biological variation % (CI) limits (LD: 5.2 (4.9-5.4) %). The differences between two tubes were not medically significant and necessarily conclusive. VacuSEL serum tubes presented comparable performance with BD serum tubes.

Comparison of the accuracy of measuring blood glucose in whole blood of arteriovenous mixed blood by two kinds of blood glucose meters

BACKGROUND

Portable blood glucose meters are the main method for detecting the blood glucose status of clinical patients.

OBJECTIVE

To investigate the accuracy of detecting blood glucose in haemodialysis patients by sampling two blood glucose meters through the haemodialysis line.

METHODS

Convenient sampling was used to select 80 patients with maintenance haemodialysis. The patients were sampled through the arterial end of the haemodialysis line within three minutes of being put on the machine. One specimen was tested by glycemeter1, which can identify the type of blood in the arteries and veins, and glycemeter2, which can only detect blood glucose in the capillaries for bedside blood glucose testing. The other specimen was sent to the laboratory biochemical analyser for blood glucose testing.

RESULTS

When the blood glucose value of the first blood glucose meter (No. 1) was compared with the laboratory biochemical analyser, the correlation coefficient was r = 0.805 (p < 0.05), the out of value of the first blood glucose meter accounted for 4.4%, and the consistency reached 95% (p < 0.05). When the blood glucose value of the second blood glucose meter (No. 2) was compared with the laboratory biochemical analyser, the correlation coefficient was r = 0.800 (p < 0.05), the out of value of the second blood glucose meter accounted for 4.4%, and the consistency reached 95% (p < 0.05).

CONCLUSIONS

For patients with maintenance haemodialysis, the blood glucose values detected by the two bedside blood glucose meters using arteriovenous mixed blood in the pipeline do not affect the accuracy and can respond more realistically.

Test results comparison and sample stability study: is the BD Barricor tube a suitable replacement for the BD RST tube?

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 different 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 dehydrogenase (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.

A Review of Efforts to Improve Lipid Stability during Sample Preparation and Standardization Efforts to Ensure Accuracy in the Reporting of Lipid Measurements

Lipidomics is a rapidly growing field, fueled by developments in analytical instrumentation and bioinformatics. To date, most researchers and industries have employed their own lipidomics workflows without a consensus on best practices. Without a community-wide consensus on best practices for the prevention of lipid degradation and transformations through sample collection and analysis, it is difficult to assess the quality of lipidomics data and hence trust results. Clinical studies often rely on samples being stored for weeks or months until they are analyzed, but inappropriate sampling techniques, storage temperatures, and analytical protocols can result in the degradation of complex lipids and the generation of oxidized or hydrolyzed metabolite artifacts. While best practices for lipid stability are sample dependent, it is generally recommended that strategies during sample preparation capable of quenching enzymatic activity and preventing oxidation should be considered. In addition, after sample preparation, lipid extracts should be stored in organic solvents with antioxidants at -20 °C or lower in an airtight container without exposure to light or oxygen. This will reduce or eliminate sublimation, and chemically and physically induced molecular transformations such as oxidation, enzymatic transformation, and photon/heat-induced degradation. This review explores the available literature on lipid stability, with a particular focus on human health and/or clinical lipidomic applications. Specifically, this includes a description of known mechanisms of lipid degradation, strategies, and considerations for lipid storage, as well as current efforts for standardization and quality insurance of protocols.