•Phosphatidylethanol (PEth) is an alcohol biomarker located on erythrocytes.•Red blood cell (pRBC) transfusion elevated PEth concentrations to the ‘moderate consumption’ range.•Clinical practices ...including liver transplant should recognize pRBC as a potential source of PEth.
Phosphatidylethanol (PEth) is a marker of alcohol consumption used in clinical and forensic settings. PEth positivity in individuals expected to abstain from alcohol can have serious consequences. PEth is located on erythrocytes, thus packed red blood cell (pRBC) transfusion is a potential cause of false-positive results. This report is the first to demonstrate this phenomenon in an authentic patient who was negative for PEth immediately prior to transfusion.
Residual blood samples collected for clinical testing before and after pRBC transfusion and citrated pRBC segments were tested for PEth homologues 16:0/18:1 (POPEth) and 16:0/18:2 (PLPEth) by liquid chromatography – tandem mass spectrometry with limit of quantitation 10 ng/mL (0.01 µmol/L).
A 56-year-old male with new-onset leukemia required transfusion of 4 pRBC units on hospital days 1–2. Blood collected at admission (day 0) showed POPEth and PLPEth < 10 ng/mL (<0.01 µmol/L). Blood collected after completion of the fourth pRBC transfusion demonstrated POPEth = 57 ng/mL (0.08 µmol/L), PLPEth = 38 ng/mL (0.05 µmol/L). One citrated segment demonstrated extremely elevated PEth, supporting pRBC transfusion as the source.
This case demonstrates pRBC transfusion elevating PEth to concentrations associated with moderate alcohol consumption. Studies suggest that healthy individuals (potential donors) could have PEth concentrations sufficient to cause significant elevation of PEth from a single pRBC unit. This is concerning for populations such as liver transplant candidates who are required to abstain from alcohol, but whose disease sequelae may require pRBC transfusion.
pRBC transfusion can artificially elevate PEth into clinically and forensically relevant ranges. Individuals interpreting toxicology testing should consider recent pRBC transfusion when evaluating PEth concentrations.
•Telomere length has been investigated as a cellular aging biomarker for environmental exposure and life style factors.•Inconsistencies using the qPCR telomere length method highlight the need for a ...careful methodological analysis of the whole process.•We summarize each critical step in qPCR telomere length assay and provide guidance and recommendations based on current knowledge.•We suggest that the telomere research community collaborate on the development and implementation of standardized protocols.
Research in the last decade has explored the length of telomeres, the protective ends of eukaryotic chromosomes, as a biomarker for the cumulative effects of environmental exposures and life experiences as well as a risk factor for major diseases. With a growing interest in telomere biology across biomedical, epidemiological and public health research, it is critical to ensure that the measurement of telomere length is performed with high precision and accuracy. Of the several major methods utilized to determine telomere length, quantitative PCR (qPCR) remains the most cost-effective and suitable method for large-scale epidemiological and population studies. However, inconsistencies in recent reports utilizing the qPCR method highlight the need for a careful methodological analysis of each step of this process. In this review, we summarize each critical step in qPCR telomere length assay, including sample type selection, sample collection, storage, processing issues and assay procedures. We provide guidance and recommendations for each step based on current knowledge. It is clear that a collaborative and rigorous effort is needed to characterize and resolve existing issues related to sample storage, both before and after DNA extraction, as well as the impact of different extraction protocols, reagents and post extraction processing across all tissue types (e.g. blood, saliva, buccal swabs, etc.) to provide the needed data upon which best practices for TL analyses can be agreed upon. Additionally, we suggest that the whole telomere research community be invited to collaborate on the development and implementation of standardized protocols for the assay itself as well as for reporting in scientific journals. The existing evidence provides substantial support for the continuation of telomere research across a range of different exposures and health outcomes. However, as with any technological or methodologic advance in science, reproducibility, reliability and rigor need to be established to ensure the highest quality research.
Cell-free DNA: Preanalytical variables Bronkhorst, Abel Jacobus; Aucamp, Janine; Pretorius, Piet J.
Clinica chimica acta,
10/2015, Letnik:
450
Journal Article
Recenzirano
Since the discovery of cell-free DNA (cfDNA) in human blood, most studies have focused on diagnostic and prognostic uses of these markers for solid tumors. Except for some prenatal tests and BEAMing, ...cfDNA analysis has not yet been translated to clinical practice and routine application appears distant. This can be attributed to overlapping factors: (i) a lack of knowledge regarding the origin and function of cfDNA, (ii) insufficient molecular characterization, and (iii) the absence of an analytical consensus. In this review, we address the latter determinant and focus specifically on quantitative analysis of cfDNA. While the literature reports limited value for a single quantitative assessment, cfDNA kinetic assessment will be an essential component to qualitative characterization. In order to establish quantitative analysis for accurate kinetic assessments, process optimization and standardization are crucial. This report elucidates the most confounding variables of each preanalytic step that must be considered for optimal analysis.
•An overview of preanalytical variables that hinder the translation of quantitative cfDNA analyses to clinical practice.•Quantitative analysis of cfDNA is a poor stand-alone marker for the detection and therapy monitoring of disease.•Quantitative analysis of cfDNA is a strong auxiliary component to qualitative characterization.•Quantitative analysis of cfDNA requires optimization and universal equivalence of procedures.•Several variables that need to be considered in this endeavor are reported.
Non-cryopreservation temperature exposure (NCE) is a vital preanalytical factor for assessing plasma quality. NCE can introduce undesirable errors in clinical diagnosis or when developing biomarkers ...of diseases. Biomarkers that can effectively indicate the changes in sample quality caused by long-term NCE (0–several days) are limited. Low-molecular-weight (LMW) peptides in the plasma are modulated by endogenous proteases. These protease activities are significantly correlated with NCE temperatures and duration, indicating a potential link of these protease reactions with the preanalytical quality of plasma samples. In this study, two groups of plasma samples were aged at room temperature (RT, 57 samples) and 4 °C (69 samples) for different durations (0, 1, 2, 5, and 10 days), and LMW peptidomics were analyzed through nanopore-assisted matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The analysis revealed 10 peptides that consistently exhibited time-dependent changes, which were used to develop multiple-variable models for predicting the changes in sample quality resulting from extended NCE. These biomarker models exhibited outstanding performance in distinguishing poor-quality samples aged at both RT and 4 °C. To validate the findings, tests on samples from validation sets were conducted by analysts who were blinded to the detailed conditions, which revealed a high specificity (94.3–96.9%) and sensitivity (90.5–99.3%). These results indicate the potential of these peptides as novel biomarkers of quality control.
Digital image analysis (DIA) is impacted by the quality of tissue staining. This study examined the influence of preanalytical variables—staining protocol design, reagent quality, section attributes, ...and instrumentation—on the performance of automated DIA software. Our hypotheses were that (1) staining intensity is impacted by subtle differences in protocol design, reagent quality, and section composition and that (2) identically programmed and loaded stainers will produce equivalent immunohistochemical (IHC) staining. We tested these propositions by using 1 hematoxylin and eosin stainer to process 13 formalin-fixed, paraffin-embedded (FFPE) mouse tissues and by using 3 identically programmed and loaded immunostainers to process 5 FFPE mouse tissues for 4 cell biomarkers. Digital images of stained sections acquired with a commercial whole slide scanner were analyzed by customizable algorithms incorporated into commercially available DIA software. Staining intensity as viewed qualitatively by an observer and/or quantitatively by DIA was affected by staining conditions and tissue attributes. Intrarun and inter-run IHC staining intensities were equivalent for each tissue when processed on a given stainer but varied measurably across stainers. Our data indicate that staining quality must be monitored for each method and stainer to ensure that preanalytical factors do not impact digital pathology data quality.
Antibodies targeting programmed death receptor 1 or programmed death ligand 1 (PD-L1) have become a standard of care to treat different cancers; for some of these tumors, there is a correlation ...between tissue expression of PD-L1 and response rates in patients. Although most of the analytical challenges in the evaluation of PD-L1 expression have been standardized, preanalytical issues have been less explored. The objective of this study was to evaluate the impact of time of ischemia on the performance of 2 commonly used antibodies against PD-L1. Sixteen tonsillectomy samples were kept in ischemia for <30 minutes from sample obtention (control) and 1, 3, 6, 12, and 24 hours at room temperature before formalin fixation and paraffin embedding. Selected areas were inserted into TMA paraffin recipient blocks stained with SP142 and SP263 antibodies and evaluated by 2 blind observers. The proportion of suboptimally stained samples was significantly higher for samples with cold ischemia times 6 hours or over (
P
<0.0001). False-negative results were 25% in samples exposed to 6 hours of ischemia and raised to 34% for samples remaining in ischemia for 12 or 24 hours. When all observations were pooled, SP142 provided suboptimal results in 24% of observations and SP263 in 12.5%; this is a statistically significant difference (
P
=0.042). In conclusion, the quality of staining for PD-L1 in tonsil samples varies with the time of cold ischemia. The SP142 antibody presented a significantly lower tolerance to prolonged cold ischemia than SP263. These results reveal the relevance of controlled preanalytical processing of samples.
Prostate cancer (PCa) is the most common noncutaneous cancer in men in the Western world. In addition to accurate diagnosis, Gleason grading and tumor volume estimates are critical for patient ...management. Computer-aided detection (CADe) software can be used to facilitate the diagnosis and improve the diagnostic accuracy and reporting consistency. However, preanalytical factors such as fixation and staining of prostate biopsy specimens and whole slide images (WSI) on scanners can vary significantly between pathology laboratories and may, therefore, impact the quality of WSI and utility of CADe algorithms. We evaluated the performance of a CADe software in predicting PCa on WSIs of prostate biopsy specimens and focused on whether there were any significant differences in image quality between WSIs obtained on different scanners and specimens from different histopathology laboratories. Thirty prostate biopsy specimens from 2 histopathology laboratories in the United States were included in this study. The hematoxylin and eosin slides of the biopsy specimens were scanned on 3 scanners, generating 90 WSIs. These WSIs were then analyzed using a CADe software (INIFY Prostate, Algorithm), which identified and annotated all areas suspicious for PCa and calculated the tumor volume (percentage area of the biopsy core involved). Study pathologists then reviewed the Algorithm’s annotations and tumor volume calculation to confirm the diagnosis and identify benign glands that were misclassified as cancer (false positive) and cancer glands that were misclassified as benign (false negative). The CADe software worked equally well on WSIs from all 3 scanners and from both laboratories, with similar sensitivity and specificity. The overall sensitivity was 99.4%, and specificity was 97%. The percentage of suspicious cancer areas calculated by the Algorithm was similar for all 3 scanners. For WSIs with small foci of cancer (<1 mm), the Algorithm identified all cancer glands (sensitivity, 100%). Preanalytical factors had no significant impact on whole slide imaging and subsequent application of a CADe software. Prediction accuracy could potentially be further improved by processing biopsy specimens in a centralized histology laboratory and training the Algorithm on WSIs from the same laboratory in order to minimize variations in preanalytical factors and optimize the diagnostic performance of the Algorithm.
Analysis of formalin-fixed paraffin-embedded (FFPE) tissue by immunohistochemistry (IHC) is commonplace in clinical and research laboratories. However, reports suggest that IHC results can be ...compromised by biospecimen preanalytical factors. The National Cancer Institute’s Biospecimen Preanalytical Variables Program conducted a systematic study to examine the potential effects of delay to fixation (DTF) and time in fixative (TIF) on IHC using 24 cancer biomarkers. Differences in IHC staining, relative to controls with a DTF of 1 hr, were observed in FFPE kidney tumor specimens after a DTF of ≥2 hr. Reductions in H-score and/or staining intensity were observed for c-MET, p53, PAX2, PAX8, pAKT, and survivin, whereas increases were observed for RCC1, EGFR, and CD10. Prolonged TIF of 72 hr resulted in significantly reduced H-scores of CD44 and c-Met in kidney tumor specimens, compared with controls with 12-hr TIF. An elevated probability of altered staining intensity due to DTF was observed for nine antigens, whereas for prolonged TIF an elevated probability was observed for one antigen. Results reported here and elsewhere across tumor types and antigens support limiting DTF to ≤1 hr when possible and fixing tissues in formalin for 12–24 hr to avoid confounding effects of these preanalytical factors on IHC.
Background
The use of RNA‐based next‐generation sequencing (NGS) assays to detect gene fusions for targeted therapy has rapidly become an essential component of comprehensive molecular profiling. For ...cytology specimens, the cell block (CB) is most commonly used for fusion testing; however, insufficient cellularity and/or suboptimal RNA quality are often limiting factors. In the current study, the authors evaluated the factors affecting RNA fusion testing in cytology and the added value of smears in cases with a suboptimal or inadequate CB.
Methods
A 12‐month retrospective review was performed to identify cytology cases that were evaluated by a targeted RNA‐based NGS assay. Samples were sequenced by targeted amplicon‐based NGS for 51 clinically relevant genes on a proprietary platform. Preanalytic factors and NGS quality parameters were correlated with the results of RNA fusion testing.
Results
The overall success rate of RNA fusion testing was 92%. Of the 146 cases successfully sequenced, 14% had a clinically relevant fusion detected. NGS testing success positively correlated with RNA yield (P = .03) but was independent of the tumor fraction, the tumor size, or the number of slides used for extraction. CB preparations were adequate for testing in 45% cases, but the inclusion of direct smears increased the adequacy rate to 92%. There was no significant difference in testing success rates between smears and CB preparations.
Conclusions
The success of RNA‐based NGS fusion testing depends on the quality and quantity of RNA extracted. The use of direct smears significantly improves the adequacy of cytologic samples for RNA fusion testing for predictive biomarkers.
Cytology specimens provide a reliable source for RNA‐based next‐generation sequencing fusion assays. The addition of cytology smears significantly improves the testing success rate of cytologic samples for RNA‐based next‐generation sequencing and is an appropriate alternative for cases in which the cell block preparation is inadequate or suboptimal.
At Norwegian hospitals biomedical laboratory scientists traditionally collects blood samples. New efficiency requirements have led to a task shift to other professions, such as nurses. ...Decentralization of venous blood sampling is an example of this. There is a lack of research on decentralization of venous blood sampling in Norway. The purpose of our study was to shed light on the topic from the nurses' perspective; focusing on whether the educational institutions for nursing facilitate topics such as blood sampling and preanalytical conditions. This is an important aspect as many nurses perform venous blood sampling in their daily work. A digital questionnaire was prepared for nurses and nursing students to investigate what kind of instruction they received in blood sampling at their educational institution, and whether this included preanalytical knowledge. In addition, the aim was to gain insight into their experience with venous blood sampling situations and attitudes to performing venous blood sampling on patients. Our results showed that 80% of all respondents (n=528) had a positive attitude towards performing venous blood sampling themselves and 68% were not satisfied with the amount of training they received during nursing school. More than half felt that they had insufficient knowledge of pre-analytical conditions to ensure correct analytical results and 83% saw venous blood sampling as a natural part of their tasks. Including blood sampling on the agenda during nursing school is important if the trend of decentralization of blood sampling continues in Norway. The educational institutions for nursing is the first step in an important work towards ensuring correct patient treatment.
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