Influence of centrifugation conditions on the results of 77 routine clinical chemistry analytes using standard vacuum blood collection tubes and the new BD-Barricor tubes

Validation of Becton Dickinson Barricor™ tubes for use with Abbott Alinity™ and Siemens Atellica® highly sensitive cardiac troponin I measuring systems

BACKGROUND

BD Barricor™ tubes have been proposed to decrease laboratory turnaround time (TAT). We analytically validated and then clinically verified these tubes for use with Abbott Alinity™ and Siemens Atellica® highly sensitive cardiac troponin I (hs-cTnI) assays.

METHODS

hs-cTnI measurements were undertaken in paired Barricor™ and in-use PSTII™ tubes on both systems. 359 matched samples with hs-cTnI levels between 3 and 15,000 ng/L (Atellica® values) were used to assess the hemolysis rate and make method comparisons. 599 paired patient samples were collected on emergency department (ED) admission to compare the performance of the rapid acute myocardial infarction (AMI) rule-out strategy based on hs-cTnI concentrations lower than recommended thresholds (<4 ng/L Alinity™; <5 ng/L Atellica®) when different tubes and systems were employed.

RESULTS

No between-tube differences in hemolysis rate were seen when free hemoglobin concentrations in plasma samples were ≥0.25 g/L, even if PSTII™ showed a significant increase of hemolysis rate vs. Barricor™ (31% vs. 22%, p=0.007) when a lower cut-off for hemolysis (≥0.11 g/L) was employed on the Atellica® detection system. The alternate use of these tubes did not influence the hs-cTnI results obtained from either of the two assays, which remained markedly biased (~40%) irrespective of the tube used. The expected optimal ability of very low hs-cTnI values on ED admission for ruling out AMI was confirmed by using both systems regardless of the tube type.

CONCLUSIONS

Barricor™ and PSTII™ tubes can provide analytically equivalent hs-cTnI results when used on either Alinity™ or Atellica® hs-cTnI assays.

Optimized protocol for quantification of extracellular nicotinamide adenine dinucleotide: evaluating clinical parameters and pre-analytical factors for translational research

Nicotinamide adenine dinucleotide (NAD+), a coenzyme for more than 500 enzymes, plays a central role in energy production, metabolism, cellular signaling, and DNA repair. Until recently, NAD+ was primarily considered to be an intracellular molecule (iNAD+), however, its extracellular species (eNAD+) has recently been discovered and has since been associated with a multitude of pathological conditions. Therefore, accurate quantification of eNAD+ in bodily fluids such as plasma is paramount to answer important research questions. In order to create a clinically meaningful and reliable quantitation method, we analyzed the relationship of cell lysis, routine clinical laboratory parameters, blood collection techniques, and pre-analytical processing steps with measured plasma eNAD+ concentrations. Initially, NAD+ levels were assessed both intracellularly and extracellularly. Intriguingly, the concentration of eNAD+ in plasma was found to be approximately 500 times lower than iNAD+ in peripheral blood mononuclear cells (0.253 ± 0.02 μM vs. 131.8 ± 27.4 μM, p = 0.007, respectively). This stark contrast suggests that cellular damage or cell lysis could potentially affect the levels of eNAD+ in plasma. However, systemic lactate dehydrogenase in patient plasma, a marker of cell damage, did not significantly correlate with eNAD+ (n = 33; r = -0.397; p = 0.102). Furthermore, eNAD+ was negatively correlated with increasing c-reactive protein (CRP, n = 33; r = -0.451; p = 0.020), while eNAD+ was positively correlated with increasing hemoglobin (n = 33; r = 0.482; p = 0.005). Next, variations in blood drawing, sample handling and pre-analytical processes were examined. Sample storage durations at 4°C (0-120 min), temperature (0° to 25°C), cannula sizes for blood collection and tourniquet times (0 - 120 s) had no statistically significant effect on eNAD+ (p > 0.05). On the other hand, prolonged centrifugation (> 5 min) and a faster braking mode of the centrifuge rotor (< 4 min) resulted in a significant decrease in eNAD+ levels (p < 0.05). Taken together, CRP and hemoglobin appeared to be mildly correlated with eNAD+ levels whereas cell damage was not correlated significantly to eNAD+ levels. The blood drawing trial did not show any influence on eNAD+, in contrast, the preanalytical steps need to be standardized for accurate eNAD+ measurement. This work paves the way towards robust eNAD+ measurements, for use in future clinical and translational research, and provides an optimized hands-on protocol for reliable eNAD+ quantification in plasma.

Performance of a manually operated salad spinner centrifuge for serum separation in the healthy domestic horse (Equus caballus) and southern white rhinoceros (Ceratotherium simum)

BACKGROUND

Field veterinarians and researchers studying wild species, such as the southern white rhinoceros, often work in remote areas with limited access to standard laboratory equipment, hindering the ability to measure serum analytes.

OBJECTIVES

The first objective was to produce an inexpensive, manually operated centrifuge that could accept standard laboratory tubes by modifying a consumer-grade salad spinner with low-cost materials. The second objective was to compare biochemistry analysis results obtained from equine and southern white rhinoceros serum separated by traditional laboratory and manual salad spinner centrifugation.

METHODS

We optimized the design and serum separation protocol using non-anticoagulated equine blood. Equine and rhinoceros serum samples were separated by manual salad spinner or traditional laboratory centrifugation. Measured analytes included sodium, potassium, chloride, urea nitrogen, creatinine, phosphorous, total calcium, magnesium, glucose, total protein, albumin, globulin, creatinine kinase, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, total bilirubin, bicarbonate, sorbitol dehydrogenase, and triglycerides. Results obtained from serum separated by each centrifugation technique were compared by Deming regression and Bland-Altman analyses.

RESULTS

A tube adaptor insert modeled after a swing angle rotor and a two-step salad spinner centrifugation yielded serum comparable to traditional laboratory centrifugation. For the majority of analytes, no proportional or constant biases were detected between centrifugation methods. A positive proportional bias in the measurement of ALP in serum separated by manual centrifugation was detected in both equine and rhinoceros samples.

CONCLUSIONS

Manual centrifugation with a modified salad spinner yields diagnostic quality serum suitable for the measurement of most standard biochemistry analytes.

Retrospective analysis of intra-patient laboratory variation demonstrates that the BD Vacutainer® Barricor™ blood collection tube reduces troponin variation

OBJECTIVE

The BD Vacutainer® Barricor™ plasma blood collection tube uses a mechanical separator during centrifugation to separate plasma from the cellular elements of blood. Compared to use of plasma separator tubes (PST™) with gel, Barricor™ produces a cleaner sample with less residual cellular content. We sought to determine if Barricor™ reduces pre-analytical error compared to PST™.

DESIGN & METHODS

We used a model previously published that utilizes serial differences between intra-patient measurements transformed into a Taylor series of variation vs time with the y-intercept equal to the sum of short-term analytic variation, preanalytic variation and biologic variation. The intra-patient variation of chloride, sodium, potassium, and troponin-T (hs-TnT) obtained from the Emergency Department of a large tertiary care center sampled with PST™ (May 2015-April 2018, n = 59,762 specimens) or Barricor™ (May 2018-May 2021, n = 61,512 specimens) was evaluated. All specimens were analyzed on either Roche Modular or Cobas® instruments. For each analyte, pairs of intra-patient results were tabulated and separated by 1 h intervals. The average between-pair variations were then regressed against time. We also determined the number of intra-patient outliers using the reference change value for each analyte.

RESULTS

The Barricor™ hs-TnT y-intercept (-0.0132) was significantly lower than the PST™ intercept (0.9109; p = 0.022). This was also true for chloride (y-intercept = 1.0067 in Barricor™ and 1.3431 in PST™, p = 0.037). The percentage of hs-TnT outliers was significantly lower in Barricor™ (8.32 %) vs PST™ (12.2 %; p < 0.001).

CONCLUSION

The analytical and biological variations are assumed to be steady over the study periods; we ascribe the difference in the y-intercept to the preanalytical effect of the Barricor™ tube reducing platelets and other cellular debris.

Fibrin clot interference in a human chorionic gonadotrophin assay causing a false Down syndrome screening result

Serum samples are generally used for the measurement of human chorionic gonadotrophin (hCG) to calculate second-trimester maternal screening results. Lower hCG concentrations correlate with a lower calculated risk of Down syndrome (DS). Hence, erroneously low hCG results due to fibrin clot may lead to misinterpretation. We present a 23-year-old woman with a pregnancy of 17+3 weeks. Blood was taken into the Becton-Dickinson (BD) vacutainer SST-II Advance tube (Ref: 367955). The hCG test was performed on Immulite 2000 XPi analyser (Siemens Healthcare Diagnostics Inc, Tarrytown, USA) with original reagents. The results of the same sample were found as 2566 U/L, 18,153 U/L, and 7748 U/L. Three consecutive results after removal of the small fibrin clot and recentrifugation were 18,878, 20,255, and 22,339 U/L. The risk of DS and MoM for the concentration of 2556 U/L hCG was < 1/10,000 and 0.14, respectively. For a hCG concentration of 20,255 U/L, these values were 1/5632 and 1.13, respectively. Laboratory professionals and technicians should be aware that erroneously low hCG results can be measured with the Immulite 2000 XPi due to interference from small fibrin clots. Falsely underestimated hCG values reduce the MoM values and thus the calculated risk of DS.

Introduction of BD Vacutainer® Barricor™ tubes in clinical biobanking and application of amino acid and cytokine quality indicators to Barricor plasma

OBJECTIVES

The use of BD Vacutainer® Barricor™ tubes (BAR) can reduce turnaround time (TAT) and improve separation of plasma from cellular components using a specific mechanical separator. Concentrations of amino acids (AAs) and cytokines, known to be labile during pre-analytical time delays, were compared in heparin (BAR, BD Heparin standard tube [PST]), EDTA and serum gel tubes (SER) to validate previously identified quality indicators (QIs) in BAR.

METHODS

Samples of healthy individuals (n=10) were collected in heparin, EDTA and SER tubes and exposed to varying pre- and post-centrifugation delays at room temperature (RT). Cytokines (interleukin [IL]-8, IL-16 and sCD40L) were analyzed by enzyme-linked immunosorbent assay (ELISA) and AAs were characterized by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS).

RESULTS

All QIs, AAs/AA ratio and cytokines increased during prolonged blood storage in heparin plasma (PST, BAR) and SER tubes. Comparison of 53 h/1 h pre-centrifugation delay resulted in an increase in taurine (Tau) and glutamic acid (Glu) concentrations by more than three times, soluble CD40L increased by 13.6, 9.2 and 4.3 fold in PST, BAR-CTRL and BAR-FAST, and IL-8 increased even more by 112.8 (PST), 266.1 (BAR-CTRL), 268.1 (BAR-FAST) and 70.0 (SER) fold, respectively. Overall, compared to prolonged blood storage, effects of post-centrifugation delays were less pronounced in all tested materials.

CONCLUSIONS

BAR tubes are compatible with the use of several established QIs and can therefore be used in clinical biobanking to reduce pre-analytical TAT without compromising QIs and thus pre-analytical sample quality analysis.

Evaluation of the Barricor Tube in 28 Routine Chemical Tests and Its Impact on Turnaround Time in an Outpatient Clinic

Background

We recently introduced the Barricor (BD, Franklin Lakes, NJ, USA) plasma separation tube, which uses a mechanical separator instead of a gel. We evaluated the effects of using the Barricor tube in a stat (statin) laboratory on the results and turnaround time (TAT) of routine chemical tests. We verified the impact of Barricor tube on reducing TAT and providing results similar to those obtained using serum separator tubes (SSTs).

Methods

We collected venous blood samples from 166 outpatients in Barricor tubes and SSTs and measured 28 routine analytes using an AU5800 instrument (Beckman Coulter, Brea, CA, USA). TAT indexes were compared before and after using Barricor tube.

Results

Mean percent differences were <5%, except for alanine aminotransferase , total CO₂, high-density lipoprotein, phosphate, total protein, and direct bilirubin. The median TAT decreased from 45 to 38 minutes, and the rate of a TAT >60 minutes decreased from 7.84% to 2.66%, which was approximately one-third of that for SST. The reduction in TAT was attributable to a decrease in centrifugation time. Incomplete clotting and repeated centrifugation, which occurred frequently when using SST, also decreased after using the Barricor tubes.

Conclusions

The Barricor tube is an alternative to SST for routine chemical tests in institutions aiming to reduce TAT, with clinically allowable differences in test results.

Comparative study of chemical pathology sample collection tubes at the largest hospital in South Africa

Background

Barricor^TM Lithium heparin plasma tubes are new blood tubes that have been introduced to overcome the effects of gel in serum separator tubes (SST) and the shortcomings of standard Lithium heparin plasma. We aimed to evaluate Barricor^TM tubes as an alternative to serum separator tubes and compare the stability between the tubes.

Methods

Forty-four paired samples were collected using both Barricor^TM and SST. We compared five analytes at baseline (<6 h) and after every 24 h using the PassingBablok and Bland-Altman plots. Aspartate aminotransferase (AST), potassium (K), phosphate (PO4) , lactate dehydrogenase (LDH), and creatinine were analysed in both tubes. We calculated the percentage difference for each analyte between the baseline and time intervals to assess analyte stability. The percentage difference was compared to the desirable specification for bias and reference change value (RCV).

Results

All analytes were comparable at baseline. Statistical differences (p<0.001) became evident after 24 h. PO4, K, and creatinine had a mean difference that exceeded the desirable specification for bias (-9.59%, - 9.35%, and -4.59%, respectively). Potassium was stable up to 24 h in both tubes. LDH showed better stability in SST (144 h vs 96 h). PO4 concentrations were more stable in both tubes with the SST (96 h vs 72 h). Creatinine and AST had the longest stability in both tubes compared to other analytes (144 h).

Conclusions

Data demonstrated variability and similarities in analyte concentrations and stability, respectively, in both tubes.

Plasma-based S100B testing for management of traumatic brain injury in emergency setting

Background

Serum biomarker S100B has been explored for its potential benefit to improve clinical decision-making in the management of patients suffering from traumatic brain injury (TBI), especially as a pre-head computed-tomography screening test for patients with mild TBI. Although being already included into some guidelines, its implementation into standard care is still lacking. This might be explained by a turnaround time (TAT) too long for serum S100B to be used in clinical decision-making in emergency settings.

Methods

S100B concentrations were determined in 136 matching pairs of serum and lithium heparin blood samples. The concordance of the test results was assessed by linear regression, Passing Pablok regression and Bland-Altman analysis. Bias and within- and between-run imprecision were determined by a 5 × 4 model using pooled patient samples. CT scans were performed as clinically indicated.

Results

Overall, S100B levels between both blood constituents correlated very well. The suitability of S100B testing from plasma was verified according to ISO15189 requirements. Using a cut-off of 0.105 ng/ml, a sensitivity and negative predictive value of 100% were obtained for identifying patients with pathologic CT scans. Importantly, plasma-based testing reduced the TAT to 26 min allowing for quicker clinical decision-making. The clinical utility of integrating S100B in TBI management is highlighted by two case reports.

Conclusions

Plasma-based S100B testing compares favorably with serum-based testing, substantially reducing processing times as the prerequisite for integrating S100B level into management of TBI patients. The proposed new clinical decision algorithm for TBI management needs to be validated in further prospective large-scale studies.

•

Plasma-based S100B testing reduces turnaround time to 26 minutes and thus enables its use in the emergency department.

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Plasma- and serum-based S100B testing demonstrate commutability of results.

•

Clinical cases demonstrate the benefit of elevated S100B levels as an indicator for second-look CT re-evaluation.

Improved Sample Quality and Decreased Turnaround Time When Using Plasma Blood Collection Tubes with a Mechanical Separator in a Large University Hospital

BACKGROUND

Serum is commonly used for clinical chemistry testing but many conditions can affect the clotting process, leading to poor sample quality and impaired workflow. With serum gel tubes, we found a high proportion of sample probe aspiration errors on our Beckman AU5800 analyzers. We decided to implement the BD Barricor™ plasma tubes, and we validated an off-specification centrifugation scheme and verified that results obtained for 65 chemistry and immunochemistry tests were comparable to those obtained in serum gel tubes. Finally, we evaluated the impact of this new tube on sample error rate and laboratory turnaround time.

METHODS

To validate centrifugation settings, 50 paired samples were collected in Barricor tubes and centrifuged at 1912 × g for 10 min or 5 min (off-specification). To compare serum gel tubes with Barricor plasma tubes, 119 paired samples were collected from volunteers and results were analyzed using weighed Deming regression. Finally, the proportion of aspiration errors and laboratory TAT for potassium were measured before and after implementing Barricor tubes.

RESULTS

Barricor tubes showed clinically acceptable equivalence to serum gel tubes for the studied analytes, and the off-specification centrifugation scheme did not affect the results. Implementing Barricor tubes improved the laboratory workflow by decreasing the aspiration error rates (2.01% to 0.77%, P < 0.001) and lowering hemolysis (P < 0.001). The laboratory TAT for potassium were also significantly lowered (P < 0.001).

CONCLUSION

Use of Barricor tubes instead of serum gel tubes leads to better sample quality, shorter more reproducible laboratory TAT, and decreases costs associated with error management.

Errors within the total laboratory testing process, from test selection to medical decision-making - A review of causes, consequences, surveillance and solutions

Laboratory analyses are crucial for diagnosis, follow-up and treatment decisions. Since mistakes in every step of the total testing process may potentially affect patient safety, a broad knowledge and systematic assessment of laboratory errors is essential for future improvement. In this review, we aim to discuss the types and frequencies of potential errors in the total testing process, quality management options, as well as tentative solutions for improvement. Unlike most currently available reviews on this topic, we also include errors in test-selection, reporting and interpretation/action of test results. We believe that laboratory specialists will need to refocus on many process steps belonging to the extra-analytical phases, intensifying collaborations with clinicians and supporting test selection and interpretation. This would hopefully lead to substantial improvements in these activities, but may also bring more value to the role of laboratory specialists within the health care setting.

A comparative analysis of different biofluids towards ovarian cancer diagnosis using Raman microspectroscopy

Biofluids, such as blood plasma or serum, are currently being evaluated for cancer detection using vibrational spectroscopy. These fluids contain information of key biomolecules, such as proteins, lipids, carbohydrates and nucleic acids, that comprise spectrochemical patterns to differentiate samples. Raman is a water-free and practically non-destructive vibrational spectroscopy technique, capable of recording spectrochemical fingerprints of biofluids with minimum or no sample preparation. Herein, we compare the performance of these two common biofluids (blood plasma and serum) together with ascitic fluid, towards ovarian cancer detection using Raman microspectroscopy. Samples from thirty-eight patients were analysed (n = 18 ovarian cancer patients, n = 20 benign controls) through different spectral pre-processing and discriminant analysis techniques. Ascitic fluid provided the best class separation in both unsupervised and supervised discrimination approaches, where classification accuracies, sensitivities and specificities above 80% were obtained, in comparison to 60–73% with plasma or serum. Ascitic fluid appears to be rich in collagen information responsible for distinguishing ovarian cancer samples, where collagen-signalling bands at 1004 cm⁻¹ (phenylalanine), 1334 cm⁻¹ (CH₃CH₂ wagging vibration), 1448 cm⁻¹ (CH₂ deformation) and 1657 cm⁻¹ (Amide I) exhibited high statistical significance for class differentiation (P < 0.001). The efficacy of vibrational spectroscopy, in particular Raman spectroscopy, combined with ascitic fluid analysis, suggests a potential diagnostic method for ovarian cancer.

Crocodylus porosus: a potential source of anticancer molecules

Background

Cancer remains a global threat resulting in significant morbidity and mortality despite advances in therapeutic interventions, suggesting urgency for identification of anticancer agents. Crocodiles thrive in polluted habitat, feed on germ-infested meat, are exposed to carcinogenic heavy metals, are the very few species to survive the catastrophic Cretaceous–Paleogene extinction event, yet have a prolonged lifespan and rarely been reported to develop cancer. Therefore, we hypothesised that animals living in polluted environments such as crocodiles possess anticancer molecules/mechanisms.

Methods

Crocodylus porosus was procured, blood collected, dissected and lysates prepared from internal organs. Organ lysates and sera were tested for growth inhibition, cytotoxic effects and cell survival against HeLa, PC3 and MCF7 cells and subjected to liquid chromatography mass spectrometry. RNA transcriptome analysis and differential gene analysis were performed using Galaxy Bioinformatics.

Results

Sera exhibited potent growth inhibition and cytotoxic effects against cancer cells. 80 molecules were detected from C. porosus and 19 molecules were putatively identified. Additionally, more than 100 potential anticancer peptides were identified from sera using bioinformatics based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition. Following transcriptome analysis, 14 genes in treated HeLa cells, 51 genes in treated MCF7 cells and 2 genes in treated PC3 cells, were found to be expressed, compared with untreated controls.

Conclusion

Animals residing in polluted milieus are an unexploited source for prospective pharmaceutical drugs, and could lead to identification of novel antitumour compound(s) and/or further understanding of the mechanisms of cancer resistance.

Comparison of Three Blood Collection Tubes for 35 Biochemical Analytes: The Becton Dickinson Barricor Tube, Serum Separating Tube, and Plasma Separating Tube

The Barricor tube (Becton Dickinson [BD], Sunnyvale, CA, USA) was recently developed to mechanically separate plasma by increasing the centrifugation rate. We compared the Barricor tube with existing serum- and plasma-based tubes based on 35 biochemical analytes and preanalytical turnaround time (TAT). Blood samples were collected from 30 healthy volunteers in a Barricor tube, serum separating tube (SST, Vacutainer SST II Tube 8.5 mL, #368972; BD), or plasma separating tube (PST, Vacutainer PST Tube 8.0 mL, #367964; BD) in random order. Next, 27 chemistry analytes, six immunochemistry analytes, and two cardiac markers were compared using Passing-Bablok regression and the Bland-Altman method. Preanalytical TAT was measured for each tube.

The Barricor tube exhibited bias exceeding the desirable limit for nine and four analytes compared with the SST and PST, respectively. The Barricor tube lactate dehydrogenase value showed a bias of −10.29% and −9.86% compared with that of the SST and PST, respectively. The preanalytical TAT of Barricor tube was 8.8 minutes, which was the shortest among the three tubes. The clinical performance of the Barricor tube was equivalent to that of the SST and PST for most analytes, with an apparent advantage in preanalytical TAT. When using the Barricor tube, the reference range needs to be changed for some analytes that exceed the desirable bias limit.

Biochemical, immunochemical and serology analytes validation of the lithium heparin BD Barricor blood collection tube on a highly automated Roche COBAS8000 instrument

BACKGROUND

Recently developed blood tubes with a barrier to provide plasma are becoming widespread. We compared 43 biochemical, 35 immunochemical and 7 serology analytes in a BD-Vacutainer® Barricor tube for local clinical validation of this lithium-heparin tube with a barrier.

METHODS

Samples from 70 volunteers were collected in different BD-tubes: a clot-activator tube with gel (SST), a lithium-heparin tube with gel (PST), and a lithium-heparin tube with barrier (BAR). Biases from Bland-Altman plots and 95% confidence intervals were compared with the desirable specification from the Ricos database in order to verify whether measurements from different tubes were significantly different.

RESULTS

For most of the analytes tested, the measurements using SST, PST or BAR tubes were equivalent. Only BIC, GLU, K, LAD, LPA, P, TP, CTX, Ferritin, HGH, vitD3 and ANTIS showed statistically significant, between-tubes, differences which might have clinical implication.

CONCLUSIONS

The study demonstrates that SST, PST and BAR can be used interchangeably for most of the analytes tested, including serology analytes. This allows the use of the same tube for assaying multiple analytes, increasing the laboratory efficiency while decreasing patients discomfort by minimizing blood withdrawal.

Comparison of some biochemical tests in different blood collection tubes in hemodialysis patients

Objective

Blood collection tubes (BCTs) related interferences in test results can adversely influence on patient outcomes. We compared test results of samples in BD (Becton-Dickinson, Franklin Lakes, NJ, USA) Vacutainer Serum Separator Tubes (SST), BD Vacutainer® Barricor™ Plasma BCTs (Barricor™) and BD Vacutainer® Rapid Serum Tube (RST).

Materials and methods

Thirty-two samples were obtained from patients after the hemodialysis were included in this study. Eight routine clinical chemistry parameters (AST, creatinin, urea, PTH, glucose, LDH, K, calcium) were measured on Roche Cobas Analyzer (Roche Diagnostics, North America). The results of samples obtained from RST and Barricor™ were compared with SST as reference tubes.

Results

Results of Glucose, K, Urea, PTH from the SST and Barricor™ were statistically significantly different (p = 0.017, p < 0.001, p = 0.011, p < 0.001, respectively). In addition, results of PTH, LDH from SST and RST were significantly different (p < 0.001, p = 0.019). However, statistical significance of test results was not clinically significant for the biochemical parameters.

Conclusion

Working with Barricor™ may provide not just a fast, clean, high-quality plasma samples, safety results, but also time and cost-effectivity. Therefore, these types of tubes, which are less costly than other BCTs, may be preferred to obtain plasma.

Challenges in Using Circulating Micro-RNAs as Biomarkers for Cardiovascular Diseases

Micro-RNAs (miRNAs) play a pivotal role in the development and physiology of the cardiovascular system while they have been associated with multiple cardiovascular diseases (CVDs). Several cardiac miRNAs are detectable in circulation (circulating miRNAs; c-miRNAs) and are emerging as diagnostic and therapeutic biomarkers for CVDs. c-miRNAs exhibit numerous essential characteristics of biomarkers while they are extremely stable in circulation, their expression is tissue-/disease-specific, and they can be easily detected using sequence-specific amplification methods. These features of c-miRNAs are helpful in the development of non-invasive assays to monitor the progress of CVDs. Despite significant progress in the detection of c-miRNAs in serum and plasma, there are many contradictory publications on the alterations of cardiac c-miRNAs concentration in circulation. The aim of this review is to examine the pre-analytical and analytical factors affecting the quantification of c-miRNAs and provide general guidelines to increase the accuracy of the diagnostic tests in order to improve future research on cardiac c-miRNAs.

Switching from serum to plasma: Implementation of BD Vacutainer® Barricor™ Plasma Blood Collection Tubes improves sample quality and laboratory turnaround time

BACKGROUND

For blood, most 24/7 standard (immuno)chemistry parameters are either measured in serum or in lithium heparin plasma. Standard serum and plasma gel tubes have their shortcomings when timely analysis of high quality results is required. Serum requires clotting time and interference of gel globules in the plasma and adsorption of hydrophobic analytes into the gel layer potentially compromises high quality results from lithium heparin gel tubes. We sought to evaluate the impact of BD Vacutainer® Barricor™ Tube (Barricor™) on laboratory efficiency by measuring its effect on TAT and sample quality, as well as evaluate potential cost opportunities resulting from improved sample quality.

METHODS

TAT data and remediation activities were extracted and captured during two 6 months phases. Serum was used as the predominant matrix in the first phase and Barricor™ plasma was used in the second phase.

RESULTS

Barricor™ significantly reduced the median TAT, especially for routine-priority samples during peak-hours. The TAT key-performance-indicator (percentage of results available within 90 ​min) improved to >90% for STAT as well as routine priority samples. Converting from serum gel, Barricor™ reduced fibrin-related remediation activities from 2.3% to 0.4%. This resulted in remediation-related cost reduction of €6.010,47 over the study period.

CONCLUSIONS

By implementing Barricor™, we saw a significant reduction in TAT and a reduction in fibrin-related remediation time and costs, when compared to a predominant serum workflow. The improved TAT opens up the possibility of consolidating to one single priority level, eliminating the need for the use of the STAT priority level.

Integrity of serum samples is changed by modified centrifugation conditions

Background Serum samples should be centrifuged for at least 10 min at 1300-2500 × g. Changed centrifugation conditions could compromise sample quality. The objective of this study was to compare the serum quality and turnaround time (TAT) using different centrifugation conditions. Methods The study was done in four different periods (A, B, C and D) at different conditions: for 10, 5 and 7 (A, B and C, respectively) at 2876 × g, and 7 (D) min at 4141 × g. Sample quality was assessed as the proportion of samples with: (a) aspiration errors, (b) H index >0.5 g/L and (c) suppressed reports of potassium (K) due to hemolysis. TAT was calculated for emergency samples. The proportions of samples (a), (b) and (c) were compared according to period A. Results The number of aspiration errors was significantly higher in samples centrifuged at 2876 × g for 5 min (p = 0.021) and remained unchanged when centrifuged for 7 min (p = 0.066 and 0.177, for periods C and D, respectively). In periods B, C and D, the proportion of samples with hemolysis was higher than that in period A (p-values 0.039, 0.009 and 0.042, respectively). TAT differed between all periods (p < 0.001), with the lowest TAT observed for B and D. The lowest number of samples exceeding 60-min TAT was observed in period D (p = 0.011). Conclusions The integrity of serum samples is changed with different centrifugation conditions than those recommended. Our study showed that shorter centrifugation at higher force (7 min at 4141 × g) significantly decreases TAT, with unchanged proportion of samples with aspiration errors.

A comparison of stability of chemical analytes in plasma from the BD Vacutainer® Barricor™ tube with mechanical separator versus tubes containing gel separator

BACKGROUND

There is a need of prolonged stability of certain chemical analytes in lithium heparin tubes with separators. A new tube with a mechanical separator has recently been launched (Barricor™), which according to the manufacturer may have these benefits. The aim of this study was to evaluate stability performance of this tube in comparison with plasma gel tubes under clinically realistic circumstances.

METHODS

Blood was collected in tubes containing lithium heparin with different separators; gel separator (Vacutainer^® PST™, Becton Dickinson and Vacuette^® , Greiner bio-one) and mechanical separator (Vacutainer^® Barricor™, Becton Dickinson). All tubes had an aspiration volume of 3 mL and were centrifuged at similar time and force. Tubes were transported manually or by car. Seven analytes from 122 patients were analyzed after 3 to 80 hours by Cobas c701 (Roche).

RESULTS

The Barricor™ tube showed increased stability of phosphate and potassium and similar stability of aspartate aminotransferase, glucose, homocysteine, lactate dehydrogenase, and magnesium compared with gel tubes. Maximal allowable bias for phosphate was exceeded after 68 hours for Barricor™ tubes compared with 29 or 35 hours for gel tubes and for potassium after 40 hours for Barricor™ tubes vs 9 or 12 hours for gel tubes. Transportation did not affect stability. Hemolysis index was slightly lower in Barricor tubes than in gel tubes (P = .01).

CONCLUSION

Implementing the new Barricor™ tube will improve stability of potassium and phosphate in plasma. Blood sampling facilities far from the laboratory may benefit from using these tubes, thus diminishing preanalytical errors.

Managing hemolyzed samples in clinical laboratories

Hemolysis is conventionally defined as membrane disruption of red blood cells and other blood cells that is accompanied by subsequent release of intracellular components into the serum or plasma. It accounts for over 60% of blood sample rejections in the laboratory and is the most common preanalytical error in laboratory medicine. Hemolysis can occur both in vivo and in vitro. Intravascular hemolysis (in vivo) is always associated with an underlying pathological condition or disease, and thus careful steps should always be taken by the laboratory to exclude in vivo hemolysis with confidence. In vitro hemolysis, on the other hand, is highly preventable. It may occur at all stages of the preanalytical phase (i.e. sample collection, transport, handling and storage), and may lead to clinically relevant, yet spurious, changes in patient results by interfering with laboratory measurements. Hemolysis interference is exerted through several mechanisms: (1) spectrophotometric interference, (2) release of intracellular components, (3) sample dilution and (4) chemical interference. The degree of interference observed depends on the level of hemolysis and also on the assay methodology. Recent evidence shows that preanalytical practices related to detection and management of hemolyzed samples are highly heterogeneous and need to be standardized. The Working Group for Preanalytical Phase (WG-PRE) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has published many recommendations for facilitating standardization and improvement of this important preanalytical issue. Some key EFLM WG-PRE publications related to hemolysis involve: (i) a call for more transparency and some practical recommendations for improving the harmonization of the automatic assessment of serum indices and their clinical usefulness, specifically the hemolysis index (H-index), (ii) recommendations on how to manage local quality assurance of serum or plasma hemolysis/icterus/lipemia-indices (HIL-indices) and (iii) recommendations on how to detect and manage hemolyzed samples in clinical chemistry testing. In this review we provide a comprehensive overview of hemolysis, including its causes and effects on clinical laboratory assays. Furthermore, we list and discuss the most recent recommendations aimed at managing hemolyzed samples in everyday practice. Given the high prevalence of hemolyzed blood samples, the associated costs, the great heterogeneity in how hemolysis is handled across healthcare settings, countries and continents, and increasing patient cross-border mobility, standardization and quality improvement processes aimed at combatting this important preanalytical problem are clearly warranted.

Blood sample quality

Several lines of evidence now confirm that the vast majority of errors in laboratory medicine occur in the extra-analytical phases of the total testing processing, especially in the preanalytical phase. Most importantly, the collection of unsuitable specimens for testing (either due to inappropriate volume or quality) is by far the most frequent source of all laboratory errors, thus calling for urgent strategies for improving blood sample quality and managing data potentially generated measuring unsuitable specimens. A comprehensive overview of scientific literature leads us to conclude that hemolyzed samples are the most frequent cause of specimen non-conformity in clinical laboratories (40-70%), followed by insufficient or inappropriate sample volume (10-20%), biological samples collected in the wrong container (5-15%) and undue clotting (5-10%). Less frequent causes of impaired sample quality include contamination by infusion fluids (i.e. most often saline or glucose solutions), cross-contamination of blood tubes additives, inappropriate sample storage conditions or repeated freezing-thawing cycles. Therefore, this article is aimed to summarize the current evidence about the most frequent types of unsuitable blood samples, along with tentative recommendations on how to prevent or manage these preanalytical non-conformities.

Barricor blood collection tubes are equivalent to PST for a variety of chemistry and immunoassay analytes except for lactate dehydrogenase

INTRODUCTION

The BD Barricor tube uses a novel mechanical separator designed to eliminate gel artifacts, decrease cellular contamination, and improve stability. Here, we evaluated the Barricor tube as a possible replacement for PST using Beckman Coulter analyzers under both optimal, alternative, and suboptimal centrifugation conditions based on BD recommendations.

METHODS

Paired PST and Barricor samples were collected from 4 local hospitals and processed based on site-specific preanalytical systems involving automated or manual centrifugation. Centrifugation conditions ranged from 1912 ×g for 10 min (suboptimal), 2060 g for 10 min (alternative), and 4000 ×g for 3 or 10 min (optimal). Tube volume (4.5 vs. 5.5 ml) was also assessed. Forty-three chemistry and immunochemistry analytes were measured on Beckman Coulter DxC and DxI analyzers.

RESULTS

Using an automated preanlaytical system with suboptimal spin conditions, no bias between PST and Barricor was observed for all analytes tested except lactate dehydrogenase (LD). Further investigation revealed significant increase in LD when Barricor was spun for 10 min at 1912, 2060 and 4000 ×g, ranging from +7.4-19.4% vs. PST across the entire measurement interval (87-493 U/l). Smaller tube volume was also associated with higher LD. Differences in LD occurred despite no change in other hemolysis markers such as potassium, phosphate, and AST.

CONCLUSIONS

LD is most sensitive to varying centrifugation conditions (time and speed) in Barricor tubes. We recommend that BD centrifugation protocols should be closely evaluated to determine if Barricor is equivalent to PST under local preanalytical configurations.

Improved quality of samples and laboratory turnaround time using 3.5 mL low vacuum BD Vacutainer® Barricor tubes in the emergency department

Background

Centrifugation is a consuming time step which participates to increase the turnaround time (TAT) in laboratories, likewise hemolysis sample that needs a re-sampling could delay management of patients. Recently, it has been postulated that BD Barricor™ tube could allow to decrease the centrifugation time and prevent hemolysis, two key feature to ensure high-quality results.

Aim of the study was to evaluate the impact of replacing 4 mL BD vacutainer heparin lithium tube by low vacuum 3.5 mL BD vacutainer Barricor™ tube in an emergency department (ED) on hemolysis rate and TAT.

Methods

Data of hemolysis index (HI) and TAT were compared between the first period of 15 days using 4 mL BD vacutainer heparin lithium tubes with 15 min at 2000xg as centrifugation setting and a second period of 15 days using BD vacutainer Barricor™ tube centrifuged 3 min at 4000xg.

Results

A significantly reduced time duration between reception of sample and available results in informatics lab system was observed with the reduction time of centrifugation allowed by use of Barricor™ tube compared to regular heparin lithium tubes (p < 0.001). A significative decrease in hemolysis rate also occurred in the second period as samples with HI < 10 reached from 52.5% in the first period to 68.5% (p < 0.001) in the second.

Conclusion

Low vacuum Barricor^TM tubes allowing a higher speed of centrifugation improve lab TAT without impairment of sample quality as a significant reduction of hemolysis was observed, a double advantage which is of particular interest for ED.

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Improving turnaround time and quality samples is a challenge for all laboratories.

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Hemolyzed samples occurrence is higher in the emergency department.

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Low vacuum tube can reduce the hemolysis rate of blood sampling.

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Higher speed centrifugation could reduce centrifugation time and turnaround time.

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Low vacuum Barricor tube in emergency unit improve hemolysis rate and turnaround time.

Parameters for Validating a Hospital Pneumatic Tube System

BACKGROUND

Pneumatic tube systems (PTSs) provide rapid transport of patient blood samples, but physical stress of PTS transport can damage blood cells and alter test results. Despite this knowledge, there is limited information on how to validate a hospital PTS.

METHODS

We compared 2 accelerometers and evaluated multiple PTS routes. Variabilities in PTS forces over the same routes were assessed. Response curves that demonstrate the relationship between the number and magnitude of accelerations on plasma lactate dehydrogenase (LD), hemolysis index, and potassium in PTS-transported blood from volunteers were generated. Extrapolations from these relationships were used to predict PTS routes that may be prone to false laboratory results. Historical data and prospective patient studies were compared with predicted effects.

RESULTS

The maximum recorded g-force was 10g for the smartphone and 22g for the data logger. There was considerable day-to-day variation in the magnitude of accelerations (CV, 4%-39%) within a single route. The linear relationship between LD and accelerations within the PTS revealed 2 PTS routes predicted to increase LD by ≥20%. The predicted increase in LD was similar to that observed in patient results when using that PTS route.

CONCLUSIONS

Hospital PTSs can be validated by documenting the relationship between the concentrations of analytes in plasma, such as LD, with PTS forces recorded by 3-axis accelerometers. Implementation of this method for PTS validation is relatively inexpensive, simple, and robust.

Localized surface plasmon resonance (LSPR) biosensor based on thermally annealed silver nanostructures with on-chip blood-plasma separation for the detection of dengue non-structural protein NS1 antigen

Early diagnosis of dengue biomarkers by employing a technology that is less labor- and time-intensive and offers higher sensitivity and lower limits of detection would find great significance in the developing world. Here, we report the development of a biosensor that exploits the localized surface plasmon resonance (LSPR) effect of silver nanostructures, created via thermal annealing of thin metal film, to detect dengue NS1 antigen, which appears as early as the onset of infection. The biosensor integrates membrane-based blood-plasma separation to develop lab-on-chip device that facilitates rapid diagnosis (within 30 min) of dengue NS1 antigen from a small volume (10 µL) of whole blood. The refractive index (RI) sensitivity of the LSPR biosensor was verified by using aqueous glycerol (0-100 wt%) which showed that it is sufficiently sensitive to detect 10^-3 change in RI, which is comparable to that observed with protein-protein interaction. The RI sensitivity was utilized to demonstrate protein binding by using bovine serum albumin and detection of antibody-antigen immune reaction by binding human chorionic gonadotropin antigen to immunoglobulin antibody immobilized in our LSPR biosensor. Next, we demonstrated the detection of NS1 in plasma obtained via centrifugation and in plasma separated on-chip. From 10 µL of whole blood spiked with NS1 antigen, our biosensor reliably detects 0.06 µg/mL of NS1, which lies within the clinical limit observed during the first seven days of infection, with a sensitivity of 9 nm/(µg/mL). These results confirm that the proposed LSPR biosensor can potentially be used in point-of-care dengue diagnostics.

Sample management for clinical biochemistry assays: Are serum and plasma interchangeable specimens?

The constrained economic context leads laboratories to centralize their routine analyses on high-throughput platforms, to which blood collection tubes are sent from peripheral sampling sites that are sometimes distantly located. Providing biochemistry results as quickly as possible implies to consolidate the maximum number of tests on a minimum number of blood collection tubes, mainly serum tubes and/or tubes with anticoagulants. However, depending on the parameters and their pre-analytical conditions, the type of matrix - serum or plasma - may have a significant impact on results, which is often unknown or underestimated in clinical practice. Importantly, the matrix-related effects may be a limit to the consolidation of analyses on a single tube, and thus must be known by laboratory professionals. The purpose of the present critical review is to put forward the main differences between using serum and plasma samples on clinical biochemistry analyses, in order to sensitize laboratory managers to the need for standardization. To enrich the debate, we also provide an additional comparison of serum and plasma concentrations for approximately 30 biochemistry parameters. Properties, advantages, and disadvantages of serum and plasma are discussed from a pre-analytical standpoint - before, during, and after centrifugation - with an emphasis on the importance of temperature, delay, and transport conditions. Then, differences in results between these matrices are addressed for many classes of biochemistry markers, particularly proteins, enzymes, electrolytes, lipids, circulating nucleic acids, metabolomics markers, and therapeutic drugs. Finally, important key-points are proposed to help others choose the best sample matrix and guarantee quality of clinical biochemistry assays. Moreover, awareness of the implications of using serum and plasma samples on various parameters assayed in the laboratory is an important requirement to ensure reliable results and improve patient care.

Comparison of Barricor™ vs. lithium heparin tubes for selected routine biochemical analytes and evaluation of post centrifugation stability

INTRODUCTION

Obtaining suitable results unaffected by pre- or postanalytical phases is pivotal for clinical chemistry service. We aimed comparison and stability of nine biochemical analytes after centrifugation using Barricor™ plasma tubes with mechanical separator vs standard Vacutainer® lithium heparin tubes.

MATERIALS AND METHODS

We collected samples on six healthy volunteers and nine patients from intensive care units into 6 mL plastic Vacutainer® lithium heparin tubes and 5.5 mL plastic Barricor™ plasma tubes. All tubes were centrifuged within 30 minutes after venipuncture. First, we compared results of nine biochemical analytes from lithium heparin tubes with Barricor™ tubes for each analyte using Passing-Bablok and Bland-Altman analyses. Second, we calculated the difference of analyte concentrations between baseline and time intervals in tubes stored at + 4 °C. Based on the total change limit we calculated the maximum allowable concentrations percentage change from baseline.

RESULTS

The majority of correlation coefficients were close to 0.99 indicating good correlation in the working range. Bland-Altman analyses showed an acceptable concordance for all analytes. In consequence, the Barricor™ tube might be an alternative to regular lithium heparin tube. Stability with this new generation tube is improved for eight analytes (except for aspartate aminotransferase) in comparison with regular lithium heparin tubes.

CONCLUSIONS

By using Barricor™ tubes and prompt centrifugation, supplemental analysis or re-analysis for eight analytes including alanine aminotransferase, alkaline phosphatase, C-reactive protein, high sensitivity troponin T, lactate dehydrogenase, NT-pro BNP, potassium and sodium could be performed within 72 h of specimen collection.

Quality of plasma samples and BD Vacutainer Barricor tubes: Effects of centrifugation

BACKGROUNDS

The BD Vacutainer® Barricor™ Plasma collection tube (BD Barricor) uses an innovative non-gel separation method. This study compared the plasma residual cell count (PRCC) obtained from BD Barricor and from BD PST II plasma tubes.

METHODS

Four BD Barricors and one BD PST II were collected from 40 donors. BD PST II was centrifuged at 1300g/10 min, while the BD Barricors were centrifuged at 1800g/10 min, 4000g/3 min, 4000g/7 min and 4000g/15 min. PRCC was evaluated measuring white blood cells (WBC), red blood cells (RBC) and Platelets (PLT) counts by Siemens ADVIA 2120. Cell-free hemoglobin was quantified by haemolysis index (HI) by Roche Cobas c501.

RESULTS

BD PST II Median WBC, RBC and PLT counts were 0.38 (10⁹/L), 0.0291 (10¹²/L) and 113.5 (10⁹/L), respectively. Considering the BD PST II as reference, PRCC differences were expressed as median bias percentage. WBC showed a significant reduction at all the conditions (p < 0.01), being the reductions: 63.9% (1800g/10 min), 69.9% (4000g/3 min), 75.0% (4000g/7 min) and 82.7% (4000g/15 min). RBC reductions 29.7% (1800g/10 min), 33.8% (4000g/3 min), 39.6% (4000g/7 min) and 66.4 (4000g/15 min) were all significant (p < 0.01). PLT reductions were 1.6% at 1800g/10 min (p = ns), 1.2% at 4000g/3 min (p = ns), 27.1% at 4000g/7 min (p = 0.046) and 46.6% at 4000g/15 min (p = 0.005). BD Barricor centrifuged for 7 and 15 min at 4000g showed an increased haemolysis.

CONCLUSIONS

BD Barricors plasma quality improved with increasing the centrifugation times but already at 4000g/3 min, the suggested centrifugation condition, a significant improvement was achieved.