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Introduction: Short-term clinical outcomes from SARS-CoV-2 infection are generally favorable. However, 15-20% of patients report persistent symptoms of at least 12 weeks duration, often referred to as long COVID. Population studies have also demonstrated an increased risk of incident diabetes and cardiovascular disease at 12 months following infection. While imaging studies have identified multi-organ injury patterns in patients with recovered COVID-19, their respective contributions to the disability and morbidity of long COVID is unclear. Methods: A multicenter, observational study of 215 vaccine-naïve patients with clinically recovered COVID-19, studied at 3-6 months following infection, and 133 healthy volunteers without prior SARS-CoV-2 infection. Patients with recovered COVID-19 were screened for long COVID related symptoms and their impact on daily living. Multi-organ, multi-parametric magnetic resonance imaging (MRI) and circulating biomarkers were acquired to document sub-clinical organ pathology. All participants underwent pulmonary function, aerobic endurance (6 min walk test), cognition testing and olfaction assessment. Clinical outcomes were collected up to 1 year from infection. The primary objective of this study is to identify associations between organ injury and disability in patients with long-COVID symptoms in comparison to controls. As a secondary objective, imaging and circulating biomarkers with the potential to exacerbate cardiovascular health were characterized. Discussion: Long-term sequelae of COVID-19 are common and can result in significant disability and cardiometabolic disease. The overall goal of this project is to identify novel targets for the treatment of long COVID including mitigating the risk of incident cardiovascular disease. Study registration: clinicaltrials.gov (MOIST late cross-sectional study; NCT04525404).
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Background: This study strove to assess the impact of the implementation of an accelerated diagnostic protocol (ADP), using shortened serial-testing intervals and a conventional troponin I (c-TnI) test, on emergency department (ED) length of stay (LOS). Methods: This retrospective cohort study included adults (aged ≥ 18 years) presenting to a Canadian ED with a primary complaint of cardiac chest pain between January 14, 2017 and January 15, 2019. For non-high-risk patients, the troponin delta timing decreased from 6 hours to 3 hours, and a different conventional troponin I level cut-point was implemented on January 15, 2018. The primary outcome was ED LOS. Secondary outcomes included disposition status, consultation proportions, and major adverse cardiac events within 30 days. Results: A total of 3133 patient interactions were included. Although the overall decrease in median ED LOS was not significant (P = 0.074), a significant reduction occurred in ED LOS (-33 minutes; 95% confidence interval: -53.6 to -12.4 minutes) among patients who were discharged in the post-ADP group. Consultations were unchanged between groups (36.1% before vs 33.8% after; P = 0.17). The major adverse cardiac events outcomes were unchanged across cohorts (15.9% vs 15.3%; P = 0.62). Conclusions: The implementation of an ADP, with a conventional troponin I test, for cardiac chest pain in a Canadian ED was not associated with a significant reduction of LOS for all patients; however, a significant reduction occurred for patients who were discharged, and the strategy appears safe.
Contexte: Cette étude visait à évaluer les répercussions de la mise en Åuvre d'un protocole de diagnostic accéléré avec intervalles plus courts entre les épreuves séquentielles et dosage classique de la troponine I sur la durée du séjour à l'urgence. Méthodologie: Cette étude de cohortes rétrospective a été menée chez des adultes (âgés de 18 ans ou plus) qui se sont présentés à l'urgence d'un hôpital canadien principalement pour une douleur thoracique cardiaque entre le 14 janvier 2017 et le 15 janvier 2019. Chez les patients qui n'étaient pas exposés à un risque élevé, l'intervalle de dosage de la troponine (delta) est passé de 6 heures à 3 heures, et une nouvelle valeur seuil a été utilisée pour le dosage classique de la troponine I à compter du 15 janvier 2018. Le critère d'évaluation principal était la durée du séjour à l'urgence. Les critères d'évaluation secondaires comprenaient le statut au moment de la sortie, les proportions de consultation et les événements cardiovasculaires indésirables majeurs dans les 30 jours. Résultats: Au total, 3 133 interactions avec des patients ont été incluses. Bien que la diminution globale de la durée médiane du séjour à l'urgence n'ait pas été significative (p = 0,074), une réduction significative du séjour à l'urgence (-33 minutes; intervalle de confiance à 95 % : -53,6 à -12,4 minutes) a été observée chez les patients ayant reçu leur congé appartenant au groupe dans lequel le protocole de diagnostic accéléré a été mis en Åuvre. Les consultations étaient inchangées entre les groupes (36,1 % avant vs 33,8 % après; p = 0,17). Les résultats relatifs aux événements cardiovasculaires indésirables majeurs sont demeurés inchangés dans les cohortes (15,9 % vs 15,3 %; p = 0,62). Conclusions: La mise en Åuvre d'un protocole de diagnostic accéléré, avec un dosage classique de la troponine I, en cas de douleur thoracique d'origine cardiaque, à l'urgence d'un établissement canadien ne s'est pas traduite par une réduction significative du séjour à l'urgence chez tous les patients. Une réduction significative a néanmoins été observée chez les patients qui ont reçu leur congé, et la stratégie s'est avérée sûre.
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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. This study aimed to determine detection criteria using commonly ordered tests to identify IV fluid contamination and validate the use of these criteria. METHODS: Confirmed contaminated and non-contaminated samples were used to identify patterns in laboratory results to develop criteria to detect IV fluid contamination. The proposed criteria were implemented at a tertiary care hospital laboratory to assess performance prospectively for 6 months, and applied to retrospective chemistry results from 3 hospitals and 1 community lab to determine feasibility and flagging rates. The algorithm was also tested at an external institution for transferability. RESULTS: The proposed algorithm had a positive predictive value of 92 %, negative predictive value of 91 % and overall agreement of 92 % when two or more criteria are met (n = 214). The flagging rates were 0.03 % to 0.07 % for hospital and 0.003 % for community laboratories. CONCLUSIONS: The proposed algorithm identified true contamination with low false flagging rates in tertiary care urban hospital laboratories. Retrospective and prospective analysis suggest the algorithm is suitable for implementation in clinical laboratories to identify samples with possible IV fluid contamination for further investigation.
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Algoritmos , Humanos , Estudios Retrospectivos , Laboratorios Clínicos , Estudios Prospectivos , Manejo de Especímenes/métodos , Manejo de Especímenes/normasRESUMEN
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. METHODS: Human serum and plasma matrix samples were constructed to yield hs-cTn concentrations near the female URLs for the Abbott, Beckman, Roche, and Siemens hs-cTn assays. These materials were sent (on dry ice) to 35 Canadian hospital laboratories (n = 64 instruments evaluated) participating in a larger clinical trial, with instructions for storage, handling, and monthly testing over one year. The mean concentration, standard deviation, and CV for each instrument type and an overall pooled CV for each manufacturer were calculated. RESULTS: The CVs for all individual instruments and overall were ≤ 10.0 % for two manufacturers (Abbott CVpooled = 6.3 % and Beckman CVpooled = 7.0 %). One of four Siemens Atellica instruments yielded a CV > 10.0 % (CVpooled = 7.7 %), whereas 15 of 41 Roche instruments yielded CVs > 10.0 % at the female URL of 9 ng/L used worldwide (6 cobas e411, 1 cobas e601, 4 cobas e602, and 4 cobas e801) (CVpooled = 11.7 %). Four Roche instruments also yielded CVs > 10.0 % near the female URL of 14 ng/L used in the United States (CVpooled = 8.5 %). CONCLUSIONS: The number of instruments achieving a CV ≤ 10.0 % at the female 99th-percentile URL varies by manufacturer and by instrument. Monitoring assay precision at the female URL is necessary for some assays to ensure optimal use of this threshold in clinical practice.
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Infarto del Miocardio , Humanos , Masculino , Femenino , Estudios Prospectivos , Canadá , Infarto del Miocardio/diagnóstico , Bioensayo , Troponina , Troponina T , Biomarcadores , Valores de ReferenciaRESUMEN
BACKGROUND: Minimizing hemolysis during phlebotomy ensures accurate chemistry results and reduces test cancellations and specimen recollections. We developed videos demonstrating best practices to reduce hemolysis and tested whether distribution to clinical nurse educators (CNEs) for provision to nursing staff affected the degree of specimen hemolysis in hospital inpatient units and outpatient clinics. METHODS: Videos of common blood collections demonstrating best practices to reduce hemolysis were filmed and then distributed via email link to all hospital-based CNEs in Calgary, Alberta, Canada. (https://vimeo.com/user18866730/review/159869683/a0cec9827f). Roche Cobas hemolysis index (H-index) results from specimens collected +/- 12 months from the date of video distribution were extracted from Roche Cobas IT middleware (cITM) and linked to collection location. An interrupted time series (ITS) analysis with collection location as the unit of anlaysis was used to quantify impact of video distribution on the trajectory of weekly mean log-H-index weighted by inverse variance. RESULTS: In +/- 3 months of data flanking video distribution (n = 137 241 collections), where overall impact was strongest, H-index trajectory (change in units per week) decreased immediately following video distribution (-5.7% / week, p < 0.01). This was accompanied by a 22% drop in overall H-index from the week before to the week after video distribution (y-intercept change, or gap). There was also a small but significant overall decrease in the proportion of hemolyzed specimens (-0.3%, p < 0.01). These changes were not observed at all collection locations, and in fact increases occured at some locations. CONCLUSIONS: We developed a novel and convenient educational aid that, when distributed, was associated with beneficial changes in specimen hemolysis at hospital inpatient units and outpatient clinics. Including it in ongoing nursing education will fill a knowledge gap that may help to reduce specimen hemolysis.
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Hemólisis , Flebotomía , Humanos , Flebotomía/métodos , Manejo de Especímenes/métodos , Hospitales , Alberta , Recolección de Muestras de Sangre/métodosRESUMEN
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. METHODS: Harnessing the power of big data, laboratory results were collected across populations and testing platforms to derive common adult RIs for 16 biochemical markers. A novel comprehensive approach was established, including: (a) analysis of big data from community laboratories across Canada; (b) statistical evaluation of age, sex, and analytical differences; (c) derivation of hRIs using the refineR method; and (d) verification of proposed hRIs across 9 laboratories with different instrumentation using serum and plasma samples collected from healthy Canadian adults. RESULTS: Harmonized RIs were calculated for all assays using the refineR method, except free thyroxine. Derived hRIs met proposed verification criterion across 9 laboratories and 5 manufacturers for alkaline phosphatase, albumin (bromocresol green), chloride, lactate dehydrogenase, magnesium, phosphate, potassium (serum), and total protein (serum). Further investigation is needed for some analytes due to failure to meet verification criteria in one or more laboratories (albumin [bromocresol purple], calcium, total carbon dioxide, total bilirubin, and sodium) or concern regarding excessively wide hRIs (alanine aminotransferase, creatinine, and thyroid stimulating hormone). CONCLUSIONS: We report a novel data-driven approach for RI harmonization. Findings support feasibility of RI harmonization for several analytes; however, some presented challenges, highlighting limitations that need to be considered in harmonization and big data analytics.
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Ciencia de los Datos , Laboratorios , Adulto , Humanos , Valores de Referencia , Canadá , AlbúminasRESUMEN
Background: Type 2 myocardial infarction (T2MI) occurs when myocardial oxygen demand exceeds myocardial oxygen supply. T2MIs occur more frequently and have worse outcomes compared to Type 1 myocardial infarction caused by an acute plaque rupture. No clinical trial evidence is available to guide pharmacological therapies in this high-risk population. Methods: The Rivaroxaban in Type 2 Myocardial Infarction (R2MI) trial (NCT04838808) was a trainee-led, pragmatic, pilot study that randomised patients with a T2MI to either rivaroxaban 2.5 mg twice daily or placebo. The trial was stopped early due to low recruitment. Investigators explored the challenges of conducting the trial in this population. This was supplemented by a retrospective chart review of 10,000 consecutive troponin assays undertaken during the study period. Results: Over a 1-year period, 276 patients with T2MI were screened for inclusion of which only 7 (2.5%) were randomised in the trial. Study investigators identified trial design and participant population factors that limited recruitment. These included: heterogeneity of patient presentation, poor clinical prognosis, and lack of dedicated non-trainee study personnel. The major limitation to recruitment was the frequency of identified exclusion criterion. The retrospective chart review identified 1715 patients with an elevated high-sensitivity troponin level, of which 916 (53%) were adjudicated to be related to T2MI. Of these, 94.5% possessed an exclusion criterion for the trial. Conclusion: Patients with a T2MI are challenging to recruit into clinical trials involving oral anticoagulation. Future studies should account for only â¼1 in every 20 screened individuals being a candidate for study recruitment.
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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. The purpose of this study was to demonstrate the importance to verify manufacturer's stability using serum ACE as an example. Serum was collected from 39 healthy volunteers and ACE activity levels measured at baseline, after 4 h, 1, 3, 7 days at room temperature, after 3, 7, and 14 days refrigerated at 4 °C, after 1, 2, 4 and 8 weeks frozen at -20 °C, and after three freeze/thaw cycles. An additional 42 discarded patient serum specimens were re-analyzed after 1 or 2 weeks frozen at -20 °C. To evaluate stability performance, percent difference was compared to the clinical acceptance criteria, which was defined as a ½ total allowable error of ±10.9 %. This study found serum ACE to be stable 4 h at room temperature, 14 days refrigerated at 4 °C, up to 1 week frozen at -20 °C, and up to three freeze/thaw cycles. The preferred storage condition for serum ACE is refrigerated at 4 °C as there was minimal change in percent bias over the 14 day period. The false increase observed in samples stored frozen longer than 1 week could impact clinical decision making. The stability findings differed from manufacturer claims, highlighting the importance of verifying stability, especially for esoteric testing such as serum ACE where specimens travel long distances in varying climates to reach centralized testing locations.
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Servicios de Laboratorio Clínico , Peptidil-Dipeptidasa A , Humanos , Temperatura , Manejo de Especímenes , Laboratorios ClínicosRESUMEN
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. Secondary outcomes included consultation proportions and major adverse cardiac events within 30 days of the index ED visit. Results: A total of 2640 patients presenting with chest pain were included, with 1333 in the TnI group and 1307 in the hs-TnI group. Median ED LOS decreased significantly, from 392 minutes for the TnI group, and 371 minutes for the hs-TnI group (median difference = 21 minutes; 95% confidence interval: 5.3, 36.7). The numbers of consultations and admissions were not statistically different between study periods. The major adverse cardiac events outcomes did not change following the implementation of the hs-TnI test (13.6% vs 13.1%; P = 0.71). Conclusions: The implementation of an accelerated chest pain protocol using an hs-TnI assay in a tertiary-care Canadian ED was associated with a modest reduction of LOS for all patients, and a substantial reduction of LOS for patients undergoing serial troponin testing. This strategy was safe, with no increase in adverse outcomes.
Contexte: Cette étude visait à évaluer l'introduction du dosage de la troponine I de haute sensibilité (hs-TnI) et le protocole accéléré qui lui est associé sur la durée des séjours aux urgences dans le cas des patients qui consultent pour une douleur thoracique, comparativement à un protocole diagnostique accéléré faisant appel à un test de troponine classique (TnI). Méthodologie: Nous avons mené une étude de cohorte rétrospective portant sur tous les adultes qui se sont présentés aux urgences d'un établissement urbain de soins tertiaires canadien entre le 8 novembre 2019 et le 9 novembre 2021 principalement pour une douleur thoracique d'origine cardiaque et dont le score était de 2 ou 3 à l'Échelle canadienne de triage et de gravité (ETG). Le principal critère d'évaluation était la durée du séjour au service des urgences. Les critères d'évaluation secondaires comprenaient la fréquence des consultations et les événements cardiaques indésirables majeurs dans les 30 jours ayant suivi la visite de référence aux urgences. Résultats: Au total, 2640 patients qui s'étaient présentés aux urgences pour une douleur thoracique ont été inclus, 1333 se trouvant dans le groupe TnI et 1307 dans le groupe hs-TnI. La durée médiane du séjour aux urgences a diminué considérablement, passant de 392 minutes dans le groupe TnI à 371 minutes dans le groupe hs-TnI (différence médiane de 21 minutes; intervalle de confiance [IC] à 95 % : 5,3-36,7). Les consultations et les admissions n'ont pas affiché de différence statistique entre les périodes de l'étude. Les événements cardiaques indésirables majeurs n'ont pas varié après l'introduction du dosage de la hs-TnI (13,6 % vs 13,1 %; p = 0,71). Conclusions: L'adoption d'un protocole accéléré pour la douleur thoracique à l'aide du dosage de la hs-TnI au service des urgences d'un établissement de soins tertiaires canadien a été associée à une légère réduction de la durée du séjour pour l'ensemble des patients et à une réduction substantielle de cette durée pour les patients soumis à des analyses de la troponine en série. De plus, cette stratégie était sûre sans hausse des événements indésirables.
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AIMS: An improved understanding of the pathophysiology of trastuzumab-mediated cardiotoxicity is required to improve outcomes of patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We aimed to characterize the cardiac and cardiometabolic phenotype of trastuzumab-mediated toxicity and potential interactions with cardiac pharmacotherapy. METHODS AND RESULTS: This study was an analysis of serial magnetic resonance imaging (MRI) and circulating biomarker data acquired from patients with HER2-positive early-stage breast cancer participating in a randomized-controlled clinical trial for the pharmaco-prevention of trastuzumab-associated cardiotoxicity. Circulating biomarkers (B-type natriuretic peptide, troponin I, MMP-2 and -9, GDF-15, neuregulin-1, and IGF-1) and MRI of cardiac structure and function and abdominal fat distribution were acquired prior to trastuzumab, post-cycle 4 and post-cycle 17. Ninety-four participants (51 ± 8 years) completed the study with 30 on placebo, 33 on perindopril, and 31 on bisoprolol. Post-cycle 4, global longitudinal strain deteriorated from baseline in both placebo (+2.0 ± 2.7%, P = 0.002) and perindopril (+0.9 ± 2.5%, P = 0.04), but not with bisoprolol (-0.2 ± 2.1%, P = 0.55). In all groups combined, extracellular volume fraction and GDF-15 increased post-cycle 4 (+1.3 ± 4.4%, P = 0.004; +130 ± 150%, P ≤ 0.001, respectively). However, no significant change in troponin I was detected throughout trastuzumab. In all groups combined, visceral and intermuscular fat volume increased post-cycle 4 (+7 ± 17%, P = 0.02, +8 ± 23%, P = 0.02, respectively), while muscle volume and IGF-1 decreased from post-cycle 4 to 17 (-2 ± 10%, P = 0.008, -18 ± 28%, P < 0.001, respectively). CONCLUSION: Trastuzumab results in impaired cardiac function and early myocardial inflammation. Trastuzumab is also associated with deleterious changes to the cardiometabolic phenotype which may contribute to the increased cardiovascular risk in this population.
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Neoplasias de la Mama , Cardiotoxicidad , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Cardiotoxicidad/prevención & control , Femenino , Humanos , Péptido Natriurético Encefálico/uso terapéutico , Trastuzumab/efectos adversos , Troponina IRESUMEN
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. This is costly, time consuming, and can lead to variability in acceptance criteria. While Clinical & Laboratory Standards Institute (CLSI) has a recommended guideline for reagent lot validation, it is often difficult to execute for small and rural laboratories due to limited resources. Defining the analytes required for detailed validation is important to allocate appropriate resources to ensure quality patient results. The goal of this study was to develop a standardized approach to reagent lot validation and optimize lab resources on Vitros chemistry instruments. DESIGN AND METHOD: This study consists of a retrospective and prospective analysis of reagent lot changes in dry slide chemistry analyzers (Ortho Clinical Diagnostics Vitros). Two years of retrospective reagent lot comparison data was obtained at a single site. A prospective study was conducted by assessing aliquots of 10 patient sample pools at 9 sites with Vitros analyzers. RESULTS: Of the 19 chemistry analytes evaluated, albumin, sodium, and total protein showed significant differences between reagent lots and also exceeded the pre-defined acceptance criteria. CONCLUSION: For these analytes, our recommendations are to perform a comprehensive lot validation with QC and patient samples. A simple lot validation with a reflex approach comprised of initially assaying QC can be adapted for the more stable analytes to allow achieving quality patient result in a resource constraint rural environment.
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Química Clínica/instrumentación , Química Clínica/normas , Juego de Reactivos para Diagnóstico/normas , Equipos y Suministros , Humanos , Estudios Prospectivos , Control de Calidad , Reproducibilidad de los Resultados , Estudios RetrospectivosRESUMEN
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. Results from these troponin assays were low. With the patient having elevated rheumatoid factor as a potential contributor to assay interference, the lab reanalyzed the samples using heterophile antibody blocking tubes, revealing lower hs-TnI levels. This case serves as a reminder to consider assay interference when the clinical picture is inconsistent with ischemia.
Une femme de 78 ans a eu deux fois une hausse de la troponine I à haute sensibilité (TnI hs). Deux cathétérismes cardiaques ont montré une coronaropathie non obstructive, et deux examens d'imagerie cardiaque par résonance magnétique se sont révélés normaux. Devant l'incapacité de ces examens à expliquer la hausse de la troponine I (TnI hs), d'autres échantillons de troponine ont été envoyés pour vérifier les interférences sur le dosage. Les résultats de ces dosages de la troponine étaient faibles. Puisque la présence d'un facteur rhumatoïde élevé chez la patiente a possiblement contribué à l'interférence du dosage, le laboratoire a soumis l'échantillon à une nouvelle analyse au moyen de tubes bloquant les anticorps hétérophiles. Cette dernière analyse a mis en évidence des concentrations plus faibles de TnI hs. Ce cas rappelle de tenir compte de l'interférence du dosage lorsque le tableau clinique n'est pas compatible avec l'ischémie.
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OBJECTIVES: Hydroxocobalamin (OHCob) is an antidote for cyanide poisoning in patients rescued from house fires and is known to cause interference with certain laboratory tests. Consensus is lacking on the extent of this interference and on how to handle these samples. The objectives of this study were to characterize OHCob interference across a wide range of laboratory tests and to develop protocols for identifying and reporting these samples. DESIGNS & METHODS: Patient plasma samples (n = 5) were spiked with OHCob (1.5 mg/mL) and compared to controls without this drug. A series of analytes were measured using chemistry, urinalysis, coagulation, hematology, and blood gas instruments. Dose-response testing was performed on a subset of assays that showed interferences ≥10%. RESULTS: Of the 77 analytes evaluated, 27 (35%) showed interference from OHCob, with chemistry and coagulation analytes showing the greatest effects. Of those affected, 22 analytes had a positive interference, whereas 5 analytes had negative interference. Dose-response studies showed dose-dependent increases and/or decreases consistent with initial spiking studies. Although red in colour, plasma samples with OHCob did not trigger hemolysis index flags, necessitating a special sample identification and reporting protocol. CONCLUSION: OHCob had significant effects on several analytes across different instruments. These findings led to the development of special sample handling and reporting protocols to identify OHCob samples and ensure only accurate results are released. It is vital for emergency departments to document and notify their laboratories whenever blood samples from these patients are drawn.
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Antídotos/farmacocinética , Análisis Químico de la Sangre , Hidroxocobalamina/farmacocinética , Intoxicación , Cianuro de Potasio , Antídotos/administración & dosificación , Femenino , Humanos , Hidroxocobalamina/administración & dosificación , Masculino , Intoxicación/sangre , Intoxicación/tratamiento farmacológicoRESUMEN
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. Various studies were conducted across a total of 9 laboratories using Beckman DxI800 and Access2 platforms. RESULTS: Within-laboratory precision was <10% across all target patient pool concentrations, however, DxI800 mean values were 20% higher than Access2 in the range of 3.6-44.9 ng/L. LOBs and LODs were lower on DxI800, 0.27 and 0.90 ng/L, respectively, compared to 2.9 and 3.2 ng/L, on Access2. Both showed excellent linearity across the full range. In method comparison to AccuTnI+3, DxI800 had a higher slope (0.9417 versus 0.8495) and positive bias (+18.1% versus -9.9%) compared to Access2, a trend further pronounced at concentrations <150 ng/L. At values <150 ng/L, there was good agreement with Abbott hsTnI (slope = 1.017, r = 0.932), but poor agreement with the Roche hsTnT assay (slope = 1.687, r = 0.589). Inter-laboratory split sample comparisons across 2 DxI800 and 7 Access2 sites showed close agreement, except at low concentrations <10 ng/L where DxI800 was 2.8 ng/L higher (p<0.001). CONCLUSIONS: The Beckman hsTnI assay showed robust analytical performance across different laboratories and platforms. However, discrepancies between platforms were found at low concentrations where rapid acute myocardial infarction (AMI) rule-out decisions occur. These differences have important implications for AMI risk assessment, suggesting that laboratories should develop platform-specific parameters rather than using them interchangibly.
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Análisis Químico de la Sangre/métodos , Troponina I/sangre , Biomarcadores/sangre , Femenino , Humanos , Límite de Detección , Masculino , Sensibilidad y EspecificidadRESUMEN
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). Agreement and correlation between the contemporary cTnI assays and hs-cTnI assay were assessed using regression analysis. Proportional bias was assessed using Bland-Altman plots. Concordance between the contemporary cTnI and hs-cTnI assays was determined by diagnostic contingency tables at specific cutoffs. RESULTS: Most POC cTnI assays had excellent correlation with the Abbott hs-cTnI method (r 2 = 0.955-0.970) except for Alere Triage (r 2 = 0.617), while proportional bias is evident between all cTnI assays. Overall concordance between POC contemporary cTnI assays and hs-cTnI assay was 80% to 90% at their respective 99th percentile cutoffs. The concordance increased to 90% to 95% when a fixed cutoff of 0.03 to 0.05 ng/mL was used across the assays. CONCLUSIONS: This study demonstrates poor analytical concordance between cTnI assays at the 99th percentile and supports the notion of a single clinical decision limit for cTnI and consequently standardization of diagnostic protocols despite the analytical differences among these assays.