Implementation of a High-sensitivity Troponin Assay for Adult Patients Who Present to the Emergency Department With Chest Pain: The Role of Clinical Decision Support.

Background: The objective of this study was to assess the health outcomes for patients who present to the emergency department (ED) with cardiac chest pain after the implementation of an accelerated diagnostic protocol using a high-sensitivity troponin assay (hs-TnI).

Methods: This prospective before-after cohort study used population-based linked health administrative data for adult patients who presented to a Canadian urban ED with chest pain of suspected cardiac origin over a 2-year study period. The primary outcome was ED length of stay (LOS).

Elevated Troponin T in Immune-Checkpoint Inhibitor Myositis: A Case of Mistaken Myocarditis.

A patient with metastatic renal cell carcinoma on axitinib and pembrolizumab had elevated high-sensitivity cardiac troponin T and normal high-sensitivity cardiac troponin I with unremarkable cardiac investigations. A noncardiac cause (myositis) was the likely cause for cardiac troponin T elevation. Cardiac troponin I may be a more appropriate marker to support a myocarditis diagnosis with concurrent myositis.

New solutions to old problems: A practical approach to identify samples with intravenous fluid contamination in clinical laboratories.

Objectives: Contamination with intravenous (IV) fluids is a common cause of specimen rejection or erroneous results in hospitalized patients. Identification of contaminated samples can be difficult. Common measures such as failed delta checks may not be adequately sensitive nor specific.

Effect of a High-Sensitivity Troponin I and Associated Diagnostic Protocol on Emergency Department Length of Stay: A Retrospective Cohort Study.

Background: The objective of this study was to assess the introduction of a high-sensitivity troponin I (hs-TnI) assay and its associated accelerated protocol on emergency department (ED) length of stay (LOS) for patients presenting with chest pain, compared to an accelerated diagnostic protocol using conventional troponin (TnI) testing.

Methods: We conducted a retrospective cohort study of all adults with a primary presenting complaint of chest pain of cardiac origin and a Canadian Triage and Acuity Scale score of 2 or 3, between November 8, 2019 and November 9, 2021, to a tertiary-care urban Canadian ED. The primary outcome was ED LOS.

Reference Interval Harmonization: Harnessing the Power of Big Data Analytics to Derive Common Reference Intervals across Populations and Testing Platforms.

Background: Harmonization in laboratory medicine is essential for consistent and accurate clinical decision-making. There is significant and unwarranted variation in reference intervals (RIs) used by laboratories for assays with established analytical traceability. The Canadian Society of Clinical Chemists (CSCC) Working Group on Reference Interval Harmonization (hRI-WG) aims to establish harmonized RIs (hRIs) for laboratory tests and support implementation.

The importance of verifying manufacturer's claim on specimen stability: An example in serum angiotensin converting enzyme testing.

Appropriate specimen handling is integral to quality and minimizing medical errors. Clinical laboratories often rely on manufacturer's claims for handling specimens, such as sample stability conditions. Serum angiotensin converting enzyme (ACE) is an example in which manufacturer claims and stability in the literature is limited.

Persistent Troponin Elevation in the Setting of an Elevated Rheumatoid Factor: When It Pays to Double Check.

A 78-year-old woman presented twice with high sensitivity troponin I (hs-TnI) elevation. Two cardiac catheterizations showed nonocclusive coronary artery disease, and 2 cardiac magnetic resonance imaging scans were normal. With these investigations unable to explain the troponin I (hs-TnI) elevation, alternate troponin samples were sent to check for assay interference.

Centralization of multisite reagent lot-to-lot validation for Ortho Clinical Vitros chemistry instruments.

Objective: Reagent lot-to-lot comparisons are recommended by accreditation bodies to ensure that the performance of each reagent lot meets acceptable standards for quality patient results. The general approach is comprised of performing quality control (QC) and patient comparison between the old and new reagent lots and evaluating against a pre-defined criteria. Reagent lot comparison practices are often variable despite using the same instrument across different laboratories.

Multi-platform analytical evaluation of the Beckman Coulter Access high-sensitivity troponin I assay across different laboratory sites using Barricor plasma.

Objectives: Previous analytical evaluations of the Beckman Coulter Access high sensitivity troponin (hsTn) I assay have focused on single platforms and laboratory sites. The purpose of this study was to determine assay robustness across different platforms at multiple sites, platform-specific characteristics, and equivalence to other hsTn methods in a large laboratory network.

Methods: Barricor plasma was used to assess imprecision, linearity, sensitivity (limit of blank and detection, LOB/LOD), and comparability to the conventional AccuTnI+3 and other hsTn assays.

Analytical Concordance of Diverse Point-of-Care and Central Laboratory Troponin I Assays.

Background: Cardiac troponin I (cTnI) 99th percentile cutoffs, used in the diagnosis of acute myocardial infarction, are not standardized across cTnI assays. We compared 3 point-of-care (POC) and 1 central laboratory contemporary cTnI assays against the Abbott high-sensitivity (hs) cTnI to evaluate the analytical concordance and the feasibility of using a single cutoff value for all assays.

Methods: Fresh blood samples collected from 102 inpatients in the coronary care unit were measured on central laboratory instruments (Beckman Coulter DxI AccuTnI+3 TnI, Abbott Architect hs-TnI) and cTnI POC analyzers (Alere Triage Troponin I, Radiometer AQT90, Abbott i-STAT).

Potential biomarkers of tissue hypoxia during acute hemodilutional anemia in cardiac surgery: A prospective study to assess tissue hypoxia as a mechanism of organ injury.

Purpose: Hemodilutional anemia is associated with acute kidney injury (AKI) and mortality in patients undergoing cardiac surgery by mechanisms that may include tissue hypoxia. Our hypothesis was to assess if changes in the potential hypoxic biomarkers, including methemoglobin and erythropoietin, correlated with a decrease in hemoglobin (Hb) concentration following hemodilution on cardiopulmonary bypass (CPB).

Methods: Arterial blood samples were taken from patients (n = 64) undergoing heart surgery and CPB at baseline, during CPB, following CPB, and in the intensive care unit (ICU).

Analytical sensitivity and diagnostic performance of serum protein electrophoresis on the HYDRAGEL 30 PROTEIN(E) β1-β2 Sebia Hydrasys system.

Background: Serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE) are used in the diagnosis and monitoring of plasma cell dyscrasias. IFE is considered the most sensitive method for the detection of monoclonal proteins (M-proteins), but it is not quantitative. The goal of this study was to establish the analytical sensitivity and diagnostic performance of SPE on the Sebia Hydrasys using HYDRAGEL 30 PROTEIN(E) β1-β2.

Experimental assessment of oxygen homeostasis during acute hemodilution: the integrated role of hemoglobin concentration and blood pressure.

Background: Low hemoglobin concentration (Hb) and low mean arterial blood pressure (MAP) impact outcomes in critically ill patients. We utilized an experimental model of "normotensive" vs. "hypotensive" acute hemodilutional anemia to test whether optimal tissue perfusion is dependent on both Hb and MAP during acute blood loss and fluid resuscitation, and to assess the value of direct measurements of the partial pressure of oxygen in tissue (PO).

Universal tranexamic acid therapy to minimize transfusion for major joint arthroplasty: a retrospective analysis of protocol implementation.

Purpose: Tranexamic acid (TXA) therapy can reduce red blood cell (RBC) transfusion; however, this therapy remains underutilized in many surgical patient populations. We assessed whether implementation of a protocol to facilitate universal administration of TXA in patients undergoing total hip or knee arthroplasty would reduce the incidence of RBC transfusion without increasing adverse clinical outcomes.

Methods: We implemented a quality of care policy to provide universal administration of intravenous TXA at a dose of 20 mg·kg(-1) iv to all eligible patients undergoing total hip or knee arthroplasty from October 21, 2013 to April 30, 2014.

Nitric oxide and hypoxia signaling.

Nitric oxide (NO) production is catalyzed by three distinct enzymes, namely, neuronal nitric oxide synthase (nNOS), inducible NOS (iNOS), and endothelial NOS (eNOS). The production of NO by vascular endothelium relies mainly on eNOS. Curiously, iNOS and nNOS also are relevant for vascular NO production in certain settings.

Differential HIF and NOS responses to acute anemia: defining organ-specific hemoglobin thresholds for tissue hypoxia.

Tissue hypoxia likely contributes to anemia-induced organ injury and mortality. Severe anemia activates hypoxia-inducible factor (HIF) signaling by hypoxic- and neuronal nitric oxide (NO) synthase- (nNOS) dependent mechanisms. However, organ-specific hemoglobin (Hb) thresholds for increased HIF expression have not been defined.

Is methemoglobin an inert bystander, biomarker or a mediator of oxidative stress--The example of anemia?

Acute anemia increases the risk for perioperative morbidity and mortality in critically ill patients who experience blood loss and fluid resuscitation (hemodilution). Animal models of acute anemia suggest that neuronal nitric oxide synthase (nNOS)-derived nitric oxide (NO) is adaptive and protects against anemia-induced mortality. During acute anemia, we have observed a small but consistent increase in methemoglobin (MetHb) levels that is inversely proportional to the acute reduction in Hb observed during hemodilution in animals and humans.