Evaluation of the Becton-Dickinson rapid serum tube: Does it provide a suitable alternative to lithium heparin plasma tubes?

Background: Obtaining a suitable specimen for analysis in a timely manner is pivotal in clinical chemistry service provision. Serum is recognized as the preferred specimen for most assays, but because of time constraints for completion of clotting and an increasing number of patients on anti-coagulant therapy, latent clotting or no clotting is an outcome which can lead to errors and delay in delivery of critical results. Although lithium heparin plasma has unique problems, it has become an alternative in hospital-based laboratories. Methods: The Becton-Dickinson (BD) rapid serum tube (RST) was evaluated in a hospital environment using a total of 53 participants, both healthy and anticoagulated, for 31 analytes against BD PST II and BD SST II tubes measured with Beckman DxC800 and DxI800 analyzers. Results: Most results from the RST tube were comparable with those from the SST II tube. Potassium results were closer to the PST II plasma concentrations. Incomplete and latent clotting was encountered in the RST specimens from participants (cardiac and dialysis) who had received a total of >7000 units of heparin [activated partial thromboplastin time (APTT) >150 s], warfarin/heparin combination, and specimens from cardiac surgery patients who had received a total of >25, 000 units of heparin (APTT >200 s) at the time of collection of specimens. Conclusions: The RST tube provides a suitable alternative to lithium heparin plasma tubes for most patients in a hospital environment. However, latent clotting continued to occur in specimens collected from participants who had received high concentrations of anticoagulants

Characterization of the Oral Fungal Microbiome (Mycobiome) in Healthy Individuals

The oral microbiome–organisms residing in the oral cavity and their collective genome–are critical components of health and disease. The fungal component of the oral microbiota has not been characterized. In this study, we used a novel multitag pyrosequencing approach to characterize fungi present in the oral cavity of 20 healthy individuals, using the pan-fungal internal transcribed spacer (ITS) primers. Our results revealed the “basal” oral mycobiome profile of the enrolled individuals, and showed that across all the samples studied, the oral cavity contained 74 culturable and 11 non-culturable fungal genera. Among these genera, 39 were present in only one person, 16 genera were present in two participants, and 5 genera were present in three people, while 15 genera (including non-culturable organisms) were present in ≥4 (20%) participants. Candida species were the most frequent (isolated from 75% of participants), followed by Cladosporium (65%), Aureobasidium, Saccharomycetales (50% for both), Aspergillus (35%), Fusarium (30%), and Cryptococcus (20%). Four of these predominant genera are known to be pathogenic in humans. The low-abundance genera may represent environmental fungi present in the oral cavity and could simply be spores inhaled from the air or material ingested with food. Among the culturable genera, 61 were represented by one species each, while 13 genera comprised between 2 and 6 different species; the total number of species identified were 101. The number of species in the oral cavity of each individual ranged between 9 and 23. Principal component (PCO) analysis of the obtained data set followed by sample clustering and UniFrac analysis revealed that White males and Asian males clustered differently from each other, whereas both Asian and White females clustered together. This is the first study that identified the “basal mycobiome” of healthy individuals, and provides the basis for a detailed characterization of the oral mycobiome in health and disease

Gene Expression Profiles from Peripheral Blood Mononuclear Cells Are Sensitive to Short Processing Delays

In the analysis of peripheral blood gene expression, timely processing of samples is essential to ensure that measurements reflect in vivo biology, rather than ex vivo sample processing variables. The effect of processing delays on global gene expression patterns in peripheral blood mononuclear cells (PBMCs) was assessed by isolating and stabilizing PBMC-derived RNA from 3 individuals either immediately after phlebotomy or after a 4 h delay. RNA was labeled using NuGEN Ovation labeling and probed using the Affymetrix HG U133 Plus 2.0 GeneChip®. Comparison of gene expression levels (≥2-fold expression change and P < 0.05) identified 307 probe sets representing genes with increased expression and 46 indicating decreased expression after 4 h. These differentially expressed genes include many that are important to inflammatory, immunologic, and cancer pathways. Among others, CCR2, CCR5, TLR10, CD180, and IL-16 have decreased expression, whereas VEGF, IL8, SOCS2, SOCS3, CD69, and CD83 have increased expression after a 4 h processing delay. The trends in expression patterns associated with delayed processing were also apparent in an independent set of 276 arrays of RNA from human PBMC samples with varying processing times. These data indicate that the time between sample acquisition, initiation of processing, and when the RNA is stabilized should be a prime consideration when designing protocols for translational studies involving PBMC gene expression analysis