Yang, Yifei

Context.— Transporting specimens can expose them to uncontrolled environmental factors. Whole blood viability is a commonly used preanalytic marker of quality for analysis of white blood cells. Objective.— To evaluate whole blood viability as a marker for transportation and specimen integrity for lymphocyte subset evaluation. Design.— More than 9000 whole blood specimens, transported during a 4-year period, and their lymphocyte subset evaluation results were analyzed retrospectively. Viability was measured by using Cellaca MX imaging cytometer, and lymphocyte and lymphocyte subset counts were determined with flow cytometry. Specimen cell viability results were stratified based on different transportation factors to discern their potential effects. Lymphocyte subset evaluation results from specimens with lower viability were compared with those from optimal viability specimens. Results.— Cell viability of transported specimens exhibited seasonal variation, decreasing during the warm summer months (median, 77.0% versus 83.4% in other seasons). The decline in viability negatively correlated with ambient temperature during transportation ( r = −0.7876). Longer transportation time (>60 hours) also caused a decrease in viability (median, 64.0%). While we observed a decrease in absolute cell counts for CD45 + lymphocytes, CD3 + T cells, CD8 + T cells, and CD19 + B cells in specimens with low viability (50%–80%), the differences were well within the assay’s total allowable error. Conclusions.— Control of preanalytic factors is critical for laboratory testing. Whole blood viability is a sensitive indicator of transport conditions and time, but it is not a specific predictor of quality for the main lymphocyte populations in cellular immunology testing.

Abstract Background Protein biomarkers are routinely measured for disease diagnosis and prognosis in clinical laboratories. Since most assays focus on protein quantity, information about proteoforms is often not acquired. Proteoforms of a protein represent the complex integration of genetic polymorphism, alternative splicing of RNA transcripts, and post-translational modifications (PTMs) on the amino-acid backbone. A detailed analysis of the post-translationally modified proteoforms (PTMPs), which are influenced by pathophysiological conditions, may lead to more precise diagnosis and prognosis. Content This article first discusses the methodologies used to accurately detect and characterize PTMPs, i.e., immunoassays, electrophoresis, chromatography, and intact and proteolysis-aided mass spectrometry techniques. Then it reviews specific examples of PTMP biomarkers that have been successfully translated from biomarker discovery to clinical use. The examples include β2–transferrin for cerebrospinal fluid leak diagnosis, phosphorylated tau proteoforms for Alzheimer disease diagnosis, and fucosylated alpha-fetoprotein for hepatocellular carcinoma prognosis. In addition, the article provides prospective views of novel analytical technologies and promising new PTMP biomarkers entering clinical practice. Summary In summary, PTMs are controlled by biochemical processes to modulate the functions of proteins by expanding their chemical diversity. PTM alterations in proteins can be indicators for pathophysiological conditions. Advances in analytical technologies are deepening our understanding of PTMPs and paving the way for their translation to clinical use. As research continues to discover the clinical meaning of PTMP biomarkers, they are poised to become valuable additions to the clinical testing menu for precision medicine.

Abstract Objectives Urine drug testing (UDT) is a critical tool used in medical, forensic, and occupational settings, but interpreting results can be challenging. We performed a study to assess the ability of health care professionals to interpret UDT results accurately. Methods In total, 911 clinical and laboratory professionals in the United States and Canada responded to a survey with questions gauging expertise in UDT interpretation. Responses were analyzed to identify knowledge gaps. Results Toxicologists and laboratory PhD scientists performed well, with means of 4.82 and 4.63 questions answered correctly (out of 6 possible), respectively. Physicians specializing in pathology, emergency medicine, primary care, and internal medicine, however, displayed concerning knowledge gaps, as did laboratorians with nondoctoral degrees. Experience and training correlated with interpretation accuracy. Identification of simulated compliance as well as understanding opioid exposure, metabolism, and immunoassay cross-reactivity were among the most clinically significant knowledge gaps. More than 30% of survey respondents indicated that they would seek UDT information from the internet or peers rather than clinical or laboratory experts. Conclusions The study highlighted the need for targeted education and better collaboration between clinical and laboratory experts and other health care professionals to ensure that when physicians order UDT, they can accurately interpret results and reduce harm.