Imprecision of high-sensitivity cardiac troponin assays at the female 99th-percentile.

Background: An analytical benchmark for high-sensitivity cardiac troponin (hs-cTn) assays is to achieve a coefficient of variation (CV) of ≤ 10.0 % at the 99th percentile upper reference limit (URL) used for the diagnosis of myocardial infarction. Few prospective multicenter studies have evaluated assay imprecision and none have determined precision at the female URL which is lower than the male URL for all cardiac troponin assays.

Importance of Adequate qPCR Controls in Infection Control.

Respiratory screening assays lacking Sample Adequacy Controls (SAC) may result in inadequate sample quality and thus false negative results. The non-adequate samples might represent a significant proportion of the total performed tests, thus resulting in sub-optimal infection control measures with implications that may be critical during pandemic times. The quantitative sample adequacy threshold can be established empirically, measuring the change in the frequency of positive results, as a function of the numerical value of "sample adequacy".

The association between glycaemic control during hospitalization and risk of adverse events: A retrospective cohort study.

Introduction: Hyperglycaemia is common during hospitalization; glycaemic targets in non-critical care settings have not been well studied. We assessed associations between inpatient glycaemic control and adverse events.

Methods: We conducted a retrospective cohort study on non-critically ill medical patients hospitalized in a tertiary care hospital between 2015 and 2018.

Sample Adequacy Control (SAC) Lowers False Negatives and Increases the Quality of Screening: Introduction of "Non-Competitive" SAC for qPCR Assays.

Sample Adequacy Control (SAC) has critical analytical, clinical and epidemiological value that increases confidence in a negative test result. The SAC is an integral qPCR assay control, which ensures that all pre-analytical and analytical steps are adequate for accurate testing and reporting. As such, a negative SAC with a negative result on pathogen screen specifies that the result should be reported as inconclusive instead of negative.

Muscle Mass and Direct Oral Anticoagulant Activity in Older Adults With Atrial Fibrillation.

Background: Direct oral anticoagulants (DOAC) are hydrophilic drugs with plasma levels inversely proportional to lean body mass. Sarcopenic patients with low muscle mass may be at risk for supra-therapeutic DOAC levels and bleeding complications. We therefore sought to examine the influence of lean body mass on DOAC levels in older adults with atrial fibrillation (AF).

Association of Serum 25-Hydroxyvitamin D With Prevalence, Incidence, and Clearance of Vaginal HPV Infection in Young Women.

Background: We assessed the association between serum 25-hydroxyvitamin D levels and genital human papillomavirus (HPV) prevalence, incidence, and clearance among female participants in the HPV Infection and Transmission among Couples through Heterosexual activity (HITCH) Cohort Study.

Methods: We genotyped HPV DNA in vaginal samples and quantified baseline serum 25-hydroxyvitamin D levels using Roche's Linear Array and Total vitamin D assay, respectively. We used logistic and Cox proportional hazards models, respectively, to estimate adjusted odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs).

Characterization and heme oxygenase-1 content of extracellular vesicles in human biofluids.

Heme oxygenase-1 (HO-1), a highly inducible stress protein that degrades heme to biliverdin, carbon monoxide, and free ferrous iron, is increased in blood and other biofluids of subjects with various systemic and neurological disorders. HO-1 does not contain an N-terminal signal peptide and the mechanism responsible for its secretion remains unknown. Extracellular vesicles (EVs) are membrane-bound inclusions that transport microRNAs, messenger RNAs, lipids, and proteins among diverse cellular and extracellular compartments.

An LC-MRM assay for the quantification of metanephrines from dried blood spots for the diagnosis of pheochromocytomas and paragangliomas.

The quantitation of metanephrine (MN), normetanephrine (NMN), and 3-methoxytyramine (3-MT) - referred to as metanephrines -- by LC-MS/MS is the gold-standard for screening for pheochromocytoma and paragangliomas (PPGLs), tumours of the adrenal gland and the peripheral nervous system. An assay for metanephrines from dried blood spots (DBSs) would be of high clinical utility as it simplifies sample collection, enables remote sampling, and could increase compliance with the clinical recommendation for supine sampling. Moreover, DBS sampling facilitates the measurement of blood-derived metanephrines in pediatric patients - where DBSs are well-established - in order to diagnose neuroblastomas.

Hypersensitivity reactions to high osmolality Total Parenteral Nutrition: a case report.

Background: The full range of allergic reactions to Total Parenteral Nutrition (TPN) remains unknown. Additionally, beyond individual allergens, there may be other factors contributing to TPN hypersensitivity reactions.

Case Presentation: We present a case of a patient with negative skin testing to common TPN allergens who had recurrent urticarial reactions to TPN.

Laboratory-developed test for detection of acute Clostridium difficile infections with the capacity for quantitative sample normalization.

We describe a laboratory-developed test intended for the detection of acute Clostridium difficile infections (CDI) with the capacity for quantitative sample normalization. The test is based on the detection of the tcdB gene. However, this biomarker is also present among people without symptoms, implying that individuals with diarrhea, not caused by C.

Effect of Hemodialysis on Levels of High-Sensitivity Cardiac Troponin T.

Cardiac troponin (cTn) is essential for the diagnosis of an acute coronary syndrome (ACS). However, in end-stage renal disease (ESRD) baseline cTn levels are often elevated, and it is unknown whether the hemodialysis (HD) procedure affects cTn levels. This leaves clinicians unsure of how to interpret cTn in HD patients with cardiac ischemia.

Rectal swab screening assays of public health importance in molecular diagnostics: Sample adequacy control.

Rectal swabs are routinely used by public health authorities to screen for multi-drug resistant enteric bacteria including vancomycin-resistant enterococci (VRE) and carbapenem-resistant enterobacteriaceae (CRE). Screening sensitivity can be influenced by the quality of the swabbing, whether performed by the patient (self-swabbing) or a healthcare practitioner. One common exclusion criterion for rectal swabs is absence of "visible soiling" from fecal matter.

Successful protocol for eliminating excessive urine microscopies: Quality improvement and cost savings with physician support.

Background: Clinical laboratories are under growing pressure to provide faster turn-around-time and maintain high quality while decreasing costs. In a setting of rising test volumes, implementation of evidence-based protocols with physician cooperation and feedback may provide frameworks and support for laboratory utilization optimization. The purpose of this study was to eliminate wasteful urine microscopy by targeting physician ordering behavior, and to ensure quality of care with physician satisfaction surveys.

Appropriate vitamin D loading regimen for patients with advanced lung cancer.

Background: Most patients attending cancer clinics have hypovitaminosis D. Correcting or preventing this abnormal condition could mitigate the emotional and physical complications of their disease, but clinical trials of vitamin D therapy in this setting are hindered by the unavailability of safe, effective and practical loading dose regimens.

Methods: In this single arm open-label pharmacokinetic trial, outpatients with advanced lung cancer consumed 20,000 IU vitamin D daily with the largest meal of the day for 14 days followed by 10,000 IU per day for a further 7 days.

Effects of vitamin C and vitamin D administration on mood and distress in acutely hospitalized patients.

Background: Hypovitaminosis C and D are highly prevalent in acute-care hospitals. Malnutrition with regard to these vitamins has been linked to mood disturbance and cognitive dysfunction.

Objective: The objective was to determine whether vitamin C or D supplementation improves mood state or reduces psychological distress in acutely hospitalized patients with a high prevalence of hypovitaminosis C and D.

Vitamin C provision improves mood in acutely hospitalized patients.

Objective: Hypovitaminosis C and D are highly prevalent in acutely hospitalized patients, but the clinical significance of these biochemical abnormalities is not known. Because deficiencies of vitamin C and D have been linked to psychologic abnormalities, vitamin C or D provision could improve the mood state of acutely hospitalized patients.

Methods: Double-blind clinical trial of the effect of vitamin C (500 mg twice daily) or vitamin D (1000 IU twice daily) on mood, as assessed with a validated instrument, the Profile of Mood States.

Metabolic origin of hypovitaminosis C in acutely hospitalized patients.

Objective: Recent studies have indicated a high prevalence of hypovitaminosis C in acutely hospitalized patients. It is unclear whether hypovitaminosis C in this setting represents deficiency or tissue redistribution of the vitamin as part of the acute-phase response.

Methods: We administered vitamin C for 1 wk to acutely hospitalized, but not critically ill patients with hypovitaminosis C, on the assumption that a large increase in plasma and mononuclear leukocyte vitamin C concentrations, a decrease in metabolic markers of oxidative stress, or an improvement in psychologic mood state would implicate the initial condition as nutritional deficiency rather than tissue redistribution.

Vitamin C deficiency in a university teaching hospital.

Objectives: There is almost no information regarding the vitamin C status of patients treated in Canadian and American hospitals. We determined the prevalence and predictors of vitamin C deficiency in patients hospitalized on the acute-care wards of a Canadian teaching hospital, and tracked their plasma vitamin C concentrations while they were there.

Methods: This was a population-based cross-sectional and time course survey of 149 medical patients shortly after admission to a university teaching hospital.

Estimating pediatric glomerular filtration rates in the era of chronic kidney disease staging.

With the use of information from a database of pediatric patients with concomitant nuclear GFR and serum creatinine (Cr), estimated GFR equations were derived on the basis of local laboratory methods and population. These formulas then were compared with those recommended by the National Kidney Foundation for estimating GFR in children. For this, their ability to estimate accurately an individual's true GFR and chronic kidney disease stage, identify patients whose true GFR was <60 ml/min per 1.

Analytic evaluation and application of a novel spectrophotometric serum lithium method to a rapid response laboratory.

The authors present an evaluation of the Lithium DST spectrophotometric method developed by Thermotrace (Victoria, Australia) on a Hitachi 917 analyzer. Accuracy was assessed by method comparison with an ion-selective electrode (ISE; Roche Integra 700) (n = 80). Linearity, within-run and between-run precision, and susceptibility to interference by hemolysis, icterus, lipemia, and sodium were assessed.