Assessing fragility of statistically significant findings from randomized controlled trials assessing pharmacological therapies for opioid use disorders: a systematic review.

BACKGROUND: The fragility index is a statistical measure of the robustness or "stability" of a statistically significant result. It has been adapted to assess the robustness of statistically significant outcomes from randomized controlled trials. By hypothetically switching some non-responders to responders, for instance, this metric measures how many individuals would need to have responded for a statistically significant finding to become non-statistically significant. The purpose of this study is to assess the fragility index of randomized controlled trials evaluating opioid substitution and antagonist therapies for opioid use disorder. This will provide an indication as to the robustness of trials in the field and the confidence that should be placed in the trials' outcomes, potentially identifying ways to improve clinical research in the field. This is especially important as opioid use disorder has become a global epidemic, and the incidence of opioid related fatalities have climbed 500% in the past two decades. METHODS: Six databases were searched from inception to September 25, 2021, for randomized controlled trials evaluating opioid substitution and antagonist therapies for opioid use disorder, and meeting the necessary requirements for fragility index calculation. Specifically, we included all parallel arm or two-by-two factorial design RCTs that assessed the effectiveness of any opioid substitution and antagonist therapies using a binary primary outcome and reported a statistically significant result. The fragility index of each study was calculated using methods described by Walsh and colleagues. The risk of bias of included studies was assessed using the Revised Cochrane Risk of Bias tool for randomized trials. RESULTS: Ten studies with a median sample size of 82.5 (interquartile range (IQR) 58, 179, range 52-226) were eligible for inclusion. Overall risk of bias was deemed to be low in seven studies, have some concerns in two studies, and be high in one study. The median fragility index was 7.5 (IQR 4, 12, range 1-26). CONCLUSIONS: Our results suggest that approximately eight participants are needed to overturn the conclusions of the majority of trials in opioid use disorder. Future work should focus on maximizing transparency in reporting of study results, by reporting confidence intervals, fragility indexes, and emphasizing the clinical relevance of findings. TRIAL REGISTRATION: PROSPERO CRD42013006507. Registered on November 25, 2013.

Emergency physician gender and head computed tomography orders for older adults who have fallen.

OBJECTIVE: Physicians vary in their computed tomography (CT) scan usage. It remains unclear how physician gender relates to clinical practice or patient outcomes. The aim of this study was to assess the association between physician gender and decision to order head CT scans for older emergency patients who had fallen. METHODS: This was a secondary analysis of a prospective observational cohort study conducted in 11 hospital emergency departments (EDs) in Canada and the United States. The primary study enrolled patients who were 65 years and older who presented to the ED after a fall. The analysis evaluated treating physician gender adjusted for multiple clinical variables. Primary analysis used a hierarchical logistic regression model to evaluate the association between treating physician gender and the patient receiving a head CT scan. Secondary analysis reported the adjusted odds ratio (OR) for diagnosing intracranial bleeding by physician gender. RESULTS: There were 3663 patients and 256 physicians included in the primary analysis. In the adjusted analysis, women physicians were no more likely to order a head CT than men (OR 1.26, 95% confidence interval 0.98-1.61). In the secondary analysis of 2294 patients who received a head CT, physician gender was not associated with finding a clinically important intracranial bleed. CONCLUSIONS: There was no significant association between physician gender and ordering head CT scans for older emergency patients who had fallen. For patients where CT scans were ordered, there was no significant relationship between physician gender and the diagnosis of clinically important intracranial bleeding.

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. 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.

Validating the Emergency Department Avoidability Classification (EDAC): A cluster randomized single-blinded agreement study.

INTRODUCTION: The Emergency Department Avoidability Classification (EDAC) retrospectively classifies emergency department (ED) visits that could have been safely managed in subacute primary care settings, but has not been validated against a criterion standard. A validated EDAC could enable accurate and reliable quantification of avoidable ED visits. We compared agreement between the EDAC and ED physician judgements to specify avoidable ED visits. MATERIALS AND METHODS: We conducted a cluster randomized, single-blinded agreement study in an academic hospital in Hamilton, Canada. ED visits between January 1, 2019, and December 31, 2019 were clustered based on EDAC classes and randomly sampled evenly. A total of 160 ED visit charts were randomly assigned to ten participating ED physicians at the academic hospital for evaluation. Physicians judged if the ED visit could have been managed appropriately in subacute primary care (an avoidable visit); each ED visit was evaluated by two physicians independently. We measured interrater agreement between physicians with a Cohen's kappa and 95% confidence intervals (CI). We evaluated the correlation between the EDAC and physician judgements using a Spearman rank correlation and ordinal logistic regression with odds ratios (ORs) and 95% CIs. We examined the EDAC's precision to identify avoidable ED visits using accuracy, sensitivity and specificity. RESULTS: ED physicians agreed on 139 visits (86.9%) with a kappa of 0.69 (95% CI 0.59-0.79), indicating substantial agreement. Physicians judged 96.2% of ED visits classified as avoidable by the EDAC as suitable for management in subacute primary care. We found a high correlation between the EDAC and physician judgements (0.64), as well as a very strong association to classify avoidable ED visits (OR 80.0, 95% CI 17.1-374.9). The EDACs avoidable and potentially avoidable classes demonstrated strong accuracy to identify ED visits suitable for management in subacute care (82.8%, 95% CI 78.2-86.8). DISCUSSION: The EDAC demonstrated strong evidence of criterion validity to classify avoidable ED visits. This classification has important potential for accurately monitoring trends in avoidable ED utilization, measuring proportions of ED volume attributed to avoidable visits and informing interventions intended at reducing ED use by patients who do not require emergency or life-saving healthcare.

Derivation of the Falls Decision Rule to exclude intracranial bleeding without head CT in older adults who have fallen.

BACKGROUND: Ground-level falls are common among older adults and are the most frequent cause of traumatic intracranial bleeding. The aim of this study was to derive a clinical decision rule that safely excludes clinically important intracranial bleeding in older adults who present to the emergency department after a fall, without the need for a computed tomography (CT) scan of the head. METHODS: This prospective cohort study in 11 emergency departments in Canada and the United States enrolled patients aged 65 years or older who presented after falling from standing on level ground, off a chair or toilet seat, or out of bed. We collected data on 17 potential predictor variables. The primary outcome was the diagnosis of clinically important intracranial bleeding within 42 days of the index emergency department visit. An independent adjudication committee, blinded to baseline data, determined the primary outcome. We derived a clinical decision rule using logistic regression. RESULTS: The cohort included 4308 participants, with a median age of 83 years; 2770 (64%) were female, 1119 (26%) took anticoagulant medication and 1567 (36%) took antiplatelet medication. Of the participants, 139 (3.2%) received a diagnosis of clinically important intracranial bleeding. We developed a decision rule indicating that no head CT is required if there is no history of head injury on falling; no amnesia of the fall; no new abnormality on neurologic examination; and the Clinical Frailty Scale score is less than 5. Rule sensitivity was 98.6% (95% confidence interval [CI] 94.9%-99.6%), specificity was 20.3% (95% CI 19.1%-21.5%) and negative predictive value was 99.8% (95% CI 99.2%-99.9%). INTERPRETATION: We derived a Falls Decision Rule, which requires external validation, followed by clinical impact assessment. Trial registration: ClinicalTrials. gov, no. NCT03745755.

Quantifying the escalating impact of paramedic transported emergency department visits for opioid-related conditions in Ontario, Canada: A population-based cohort study.

INTRODUCTION: While overdoses comprise the majority of opioid research, the comprehensive impact of the opioid crisis on emergency departments (EDs) and paramedic services has not been reported. We examined temporal changes in population-adjusted incidence rates of ED visits and paramedic transports due to opioid-related conditions. MATERIALS AND METHODS: We conducted a population-based cohort study of all ED visits in the National Ambulatory Care Reporting System from January 1, 2009 to December 31, 2019 in Ontario, Canada. We included all patients with a primary diagnosis naming opioids as the underlying cause for the visit, without any other drugs or substances. We clustered geographic regions using Local Health Integration Network boundaries. Descriptive statistics, incidence rate ratios (IRR) and 95% confidence intervals (CIs) were calculated to analyze population-adjusted temporal changes. RESULTS: Overall, 86,403 ED visits were included in our study. Incidence of opioid-related ED visits increased by 165% in the study timeframe, with paramedic transported patients increasing by 429%. Per 100,000 residents, annual ED visits increased from 40.4 to 97.2, and paramedic transported patients from 12.1 to 67.9. The proportion of opioid-related ED visits transported by paramedics increased from 35.0% to 69.9%. The medical acuity of opioid-related ED visits increased throughout the years (IRR 6.8. 95% CI 5.9-7.7), though the proportion of discharges remained constant (~75%). The largest increases in ED visits and paramedic transports were concentrated to urbanized regions. DISCUSSION: Opioid-related ED visits and paramedic transports increased substantially between 2009 and 2019. The proportion of ED visits transported by paramedics doubled. Our findings could provide valuable support to health stakeholders in implementing timely strategies aimed at safely reducing opioid-related ED visits. The increased use of paramedics followed by high rates of ED discharge calls for exploration of alternative care models within paramedic systems, such as direct transport to specialized substance abuse centres.

The Clinical Validation of a Common Analytical Change Criteria for Cardiac Troponin for Ruling in an Acute Cardiovascular Outcome in Patients Presenting with Ischemic Chest Pain Symptoms.

Serial cardiac troponin (cTn) testing on patients with symptoms suggestive of acute coronary syndrome (ACS) is primarily to identify those patients with evolving myocardial injury. With the improved analytical performance of the high-sensitivity cTn (hs-cTn) assays, different change criteria have been proposed that are mostly assay dependent. Here, we developed and compared a new Common Change Criteria (3C for the combined criteria of >3 ng/L, >30%, or >15% based on the initial cTn concentration of <10 ng/L, 10 to 100 ng/L, or >100 ng/L, respectively) method, versus the 2 h assay-dependent absolute change criteria endorsed by the European Society of Cardiology (ESC), versus the common relative >20% change criterion. These different analytical change criteria were evaluated in 855 emergency department (ED) patients with symptoms of ACS and who had two samples collected 3 h apart. The cTn concentrations were measured with four different assays (Abbott hs-cTnI, Roche hs-cTnT, Ortho cTnI-ES, and Ortho hs-cTnI). The outcomes evaluated were myocardial infarction (MI) and a composite outcome (MI, unstable angina, ventricular arrhythmia, heart failure, or cardiovascular death) within 7 days of ED presentation. The combined change criteria (3C) method yielded higher specificities (range: 93.9 to 97.2%) as compared to the >20% criterion (range: 42.3 to 88.1%) for all four assays for MI. The 3C method only yielded a higher specificity estimate for MI for the cTnI-ES assay (95.9%) versus the absolute change criteria (71.7%). Similar estimates were obtained for the composite outcome. There was also substantial agreement between hs-cTnT and the different cTnI assays for MI with the 3C method, with the percent agreement being ≥95%. The Common Change Criteria (3C) method combining both absolute and different percent changes may be used with cTnI, hs-cTnT, and different hs-cTnI assays to yield similar high-specificity (rule-in) estimates for adverse cardiovascular events for patients presenting to the ED with ACS symptoms.

Personalized diagnosis in suspected myocardial infarction.

BACKGROUND: In suspected myocardial infarction (MI), guidelines recommend using high-sensitivity cardiac troponin (hs-cTn)-based approaches. These require fixed assay-specific thresholds and timepoints, without directly integrating clinical information. Using machine-learning techniques including hs-cTn and clinical routine variables, we aimed to build a digital tool to directly estimate the individual probability of MI, allowing for numerous hs-cTn assays. METHODS: In 2,575 patients presenting to the emergency department with suspected MI, two ensembles of machine-learning models using single or serial concentrations of six different hs-cTn assays were derived to estimate the individual MI probability (ARTEMIS model). Discriminative performance of the models was assessed using area under the receiver operating characteristic curve (AUC) and logLoss. Model performance was validated in an external cohort with 1688 patients and tested for global generalizability in 13 international cohorts with 23,411 patients. RESULTS: Eleven routinely available variables including age, sex, cardiovascular risk factors, electrocardiography, and hs-cTn were included in the ARTEMIS models. In the validation and generalization cohorts, excellent discriminative performance was confirmed, superior to hs-cTn only. For the serial hs-cTn measurement model, AUC ranged from 0.92 to 0.98. Good calibration was observed. Using a single hs-cTn measurement, the ARTEMIS model allowed direct rule-out of MI with very high and similar safety but up to tripled efficiency compared to the guideline-recommended strategy. CONCLUSION: We developed and validated diagnostic models to accurately estimate the individual probability of MI, which allow for variable hs-cTn use and flexible timing of resampling. Their digital application may provide rapid, safe and efficient personalized patient care. TRIAL REGISTRATION NUMBERS: Data of following cohorts were used for this project: BACC ( www. CLINICALTRIALS: gov ; NCT02355457), stenoCardia ( www. CLINICALTRIALS: gov ; NCT03227159), ADAPT-BSN ( www.australianclinicaltrials.gov.au ; ACTRN12611001069943), IMPACT ( www.australianclinicaltrials.gov.au , ACTRN12611000206921), ADAPT-RCT ( www.anzctr.org.au ; ANZCTR12610000766011), EDACS-RCT ( www.anzctr.org.au ; ANZCTR12613000745741); DROP-ACS ( https://www.umin.ac.jp , UMIN000030668); High-STEACS ( www. CLINICALTRIALS: gov ; NCT01852123), LUND ( www. CLINICALTRIALS: gov ; NCT05484544), RAPID-CPU ( www. CLINICALTRIALS: gov ; NCT03111862), ROMI ( www. CLINICALTRIALS: gov ; NCT01994577), SAMIE ( https://anzctr.org.au ; ACTRN12621000053820), SEIGE and SAFETY ( www. CLINICALTRIALS: gov ; NCT04772157), STOP-CP ( www. CLINICALTRIALS: gov ; NCT02984436), UTROPIA ( www. CLINICALTRIALS: gov ; NCT02060760).

Ninety-Day Stroke or Transient Ischemic Attack Recurrence in Patients Prescribed Anticoagulation in the Emergency Department With Atrial Fibrillation and a New Transient Ischemic Attack or Minor Stroke.

Background For patients with atrial fibrillation seen in the emergency department (ED) following a transient ischemic attack (TIA) or minor stroke, the impact of initiating oral anticoagulation immediately rather than deferring the decision to outpatient follow-up is unknown. Methods and Results We conducted a planned secondary data analysis of a prospective cohort of 11 507 adults in 13 Canadian EDs between 2006 and 2018. Patients were eligible if they were aged 18 years or older, with a final diagnosis of TIA or minor stroke with previously documented or newly diagnosed atrial fibrillation. The primary outcome was subsequent stroke, recurrent TIA, or all-cause mortality within 90 days of the index TIA diagnosis. Secondary outcomes included stroke, recurrent TIA, or death and rates of major bleeding. Of 11 507 subjects with TIA/minor stroke, atrial fibrillation was identified in 11.2% (1286, mean age, 77.3 [SD 11.1] years, 52.4% male). Over half (699; 54.4%) were already taking anticoagulation, 89 (6.9%) were newly prescribed anticoagulation in the ED. By 90 days, 4.0% of the atrial fibrillation cohort had experienced a subsequent stroke, 6.5% subsequent TIA, and 2.6% died. Results of a multivariable logistic regression indicate no association between prescribed anticoagulation in the ED and these 90-day outcomes (composite odds ratio, 1.37 [95% CI, 0.74-2.52]). Major bleeding was found in 5 patients, none of whom were in the ED-initiated anticoagulation group. Conclusions Initiating oral anticoagulation in the ED following new TIA was not associated with lower recurrence rates of neurovascular events or all-cause mortality in patients with atrial fibrillation.

Prognostic Association Between Frailty and Post-Arrest Health Outcomes in Patients Receiving Home Care: A Population-Based Retrospective Cohort Study.

AIM: To evaluate the association between frailty and post-cardiac arrest survival, functional decline, and cognitive decline, among patients receiving home care. METHODS: Frailty was measured using the Clinical Frailty Scale (CFS) and a valid frailty index. We used multivariable logistic regression to measure the association between frailty and post-arrest outcomes after adjusting for age, sex, and arrest setting. Functional independence and cognitive performance were measured using the interRAI ADL Long-Form and Cognitive Performance Scale, respectively. We conducted sub-group analytics of in-hospital and out-of-hospital arrests. RESULTS: Our cohort consisted of 7,901 home care clients; most patients arrested out-of-hospital (55.4%) and were 75 years or older (66.3%). Most were classified as frail (94.2%) with a CFS score of 5 or greater. The 30-day survival rate was higher for in-hospital (26.6%) than out-of-hospital cardiac arrests (5.2%). Most patients who survived to discharge had declines in post-arrest functional independence (65.8%) and cognitive performance (46.5%). A one-point increase in the CFS decreased the odds of 30-day survival by 8% (aOR = 0.92; 95%CI = 0.87-0.97). A 0.1 unit increase in the frailty index reduced the odds of 30-day survival by 9% (aOR = 0.91; 95%CI = 0.86-0.96). The frailty index was associated with declines in functional independence (OR = 1.16; 95%CI = 1.02-1.31) and cognitive performance (OR = 1.24; 95%CI = 1.09-1.42), while the CFS was not. CONCLUSION: Frailty is associated with cardiac arrest survival and post-arrest cognitive and functional status in patients receiving home care. Post-cardiac arrest cognitive and functional status are best predicted using more comprehensive frailty indices.

Prospective Validation of Computed Tomography to Identify Patients at High Risk for Stroke After Transient Ischemic Attack or Minor Stroke.

BACKGROUND: Computed tomography (CT) findings of acute and chronic ischemia are associated with subsequent stroke risk in patients with transient ischemic attack. We sought to validate these associations in a large prospective cohort of patients with transient ischemic attack or minor stroke. METHODS: This prospective cohort study enrolled emergency department patients from 13 hospitals with transient ischemic attack who had CT imaging. Primary outcome was stroke within 90 days. Secondary outcomes were stroke within 2 or 7 days. CT findings were abstracted from radiology reports and classified for the presence of acute ischemia, chronic ischemia, or microangiopathy. Multivariable logistic regression was used to test associations with primary and secondary end points. RESULTS: From 8670 prospectively enrolled patients between May 2010 and May 2017, 8382 had a CT within 24 hours. From this total population, 4547 (54%) patients had evidence of acute ischemia, chronic ischemia, or microangiopathy on CT, of whom 175 had a subsequent stroke within 90 days (3.8% subsequent stroke rate; adjusted odds ratio [aOR], 2.33 [95% CI, 1.62-3.36]). This was in comparison to those with CT imaging without ischemia. Findings associated with an increased risk of stroke at 90 days were isolated acute ischemia (6.0%; aOR, 2.42 [95% CI, 1.03-5.66]), acute ischemia with microangiopathy (10.7%; aOR, 3.34 [95% CI, 1.57-7.14]), chronic ischemia with microangiopathy (5.2%; aOR, 1.83 [95% CI, 1.34-2.50]), and acute ischemia with chronic ischemia and microangiopathy (10.9%; aOR, 3.49 [95% CI, 1.54-7.91]). Acute ischemia with chronic ischemia and microangiopathy were most strongly associated with subsequent stroke within 2 days (aOR, 4.36 [95% CI, 1.31-14.54]) and 7 days (aOR, 4.50 [95% CI, 1.73-11.69]). CONCLUSIONS: In patients with transient ischemic attack or minor stroke, CT evidence of acute ischemia with chronic ischemia or microangiopathy significantly increases the risk of subsequent stroke within 90 days of index visit. The combination of all 3 findings results in the greatest early risk.

Using logistic regression models to investigate the effects of high-sensitivity cardiac troponin T confounders on ruling in acute myocardial infarction.

OBJECTIVES: Confounding factors, including sex, age, and renal dysfunction, affect high-sensitivity cardiac troponin T (hs-cTnT) concentrations and the acute myocardial infarction (AMI) diagnosis. This study assessed the effects of these confounders through logistic regression models and evaluated the diagnostic performance of an optimized, integrated prediction model. METHODS: This retrospective study included a primary derivation cohort of 18,022 emergency department (ED) patients at a US medical center and a validation cohort of 890 ED patients at a Canadian medical center. Hs-cTnT was measured with 0/3 h sampling. The primary outcome was index AMI diagnosis. Logistic regression models were optimized to predict AMI using delta hs-cTnT and its confounders as covariates. The diagnostic performance of model cutoffs was compared to that of the hs-cTnT delta thresholds. Serial logistic regressions were carried out to evaluate the relationship between covariates. RESULTS: The area under the curve of the best-fitted model was 0.95. The model achieved a 90.0% diagnostic accuracy in the validation cohort. The optimal model cutoff yielded comparable performance (90.5% accuracy) to the optimal sex-specific delta thresholds (90.3% accuracy), with 95.8% agreement between the two diagnostic methods. Serial logistic regressions revealed that delta hs-cTnT played a more predominant role in AMI prediction than its confounders, among which sex is more predictive of AMI (total effect coefficient 1.04) than age (total effect coefficient 0.05) and eGFR (total effect coefficient -0.008). CONCLUSIONS: The integrated prediction model incorporating confounding factors does not outperform hs-cTnT delta thresholds. Sex-specific hs-cTnT delta thresholds remain to provide the highest diagnostic accuracy.

Inclusion of patient-level emergency department characteristics to classify potentially redirectable visits to subacute care: a modified Delphi consensus study.

BACKGROUND: Most patients transported by Ontario paramedics to the emergency department have non-emergent conditions and may be more appropriately served by subacute community-based care centres. We sought to determine consensus on a set of patient characteristics that could be useful to classify retrospective emergency department visits that had a high probability of being primary care-like and potentially redirectable to a subacute care centre by paramedics. METHODS: We conducted a modified Delphi study to assess expert consensus on characteristics of patients transported by paramedics to the emergency department from August to October 2021. An expert Delphi committee was constructed of emergency and family physicians in Ontario using purposive sampling. Experts rated whether each characteristic was useful to be included in a classification to identify potentially redirectable visits retrospectively, as well as characteristic details (e.g., upper and lower bounds). Consensus was considered 75% agreement. RESULTS: Sixteen experts participated in the study; the experts were mostly male (75%) and evenly divided between emergency and family medicine. After 2 rounds, consensus was achieved on 8 of 9 characteristics (89%). Four characteristics were determined as useful to classify potentially redirectable emergency department visits: age (81%), triage acuity (100%), specialist consult in the emergency department (94%) and emergency department visit outcome (81%). Specifications of each characteristic were refined as follows: young and middle-aged adults with a non-emergent triage acuity, did not receive a specialist physician consult in the emergency department and discharged from the emergency department. INTERPRETATION: Strong consensus was achieved to specify a classification system for potentially redirectable emergency department visits. These results will be combined with knowledge of which subacute care centres could conduct the main physician interventions to retrospectively identify emergency department visits that could have been suitable for paramedic redirection for further research. STUDY REGISTRATION: ID ISRCTN22901977.

Storage conditions, sample integrity, interferences, and a decision tool for investigating unusual high-sensitivity cardiac troponin results.

The current definition of high-sensitivity cardiac troponin (hs-cTn) assays is laboratory-based and their analytical attributes and characteristics have drawn significant attention in the literature at least partly due to the lower concentration cut-offs and changes in concentrations (i.e., deltas) employed in different algorithms and pathways to manage patient care. We propose that pre-analytical conditions such as sample type, storage conditions, and other interferences may also have a significant impact on hs-cTn concentrations and clinical management. The purpose of this literature review is to provide a summary of important pre-analytical and interference studies affecting hs-cTn concentrations. A breakdown of the literature for the major diagnostic companies providing core laboratory instrumentation (i.e., Abbott, Beckman, Ortho, Roche, and Siemens) is also provided. Finally, three cases are highlighted where knowledge of pre-analytical factors aids the hs-cTn clinically discordant investigations. This review highlights the importance of pre-analytical variables, especially storage condition, sample handling, and blood tubes used (i.e., sample type) when interpreting hs-cTn assays. Additional studies are needed to further elaborate on pre-analytical variables (i.e., centrifugation, sample type, stability) and interferences for all hs-cTn assays in clinical use, as knowledge of these variables may aid in hs-cTn clinically discordant investigations.