Pandemic Response in the Clinical Laboratory: The Utility of Interactive Dashboards.

The ability to access and analyze data is critical to manage a laboratory and respond and adapt to changes, particularly during a pandemic. Data analytic tools can not only improve laboratory operations, but also increase the visibility of the laboratory in the healthcare system and demonstrate the positive impact of the laboratory on patient care. In this article, we describe the creation and utility of laboratory dashboards. Several dashboards were designed to assist with pandemic response. For each dashboard, a stored procedure was created that performed a SQL query of our laboratory information system mirror database. We utilized the business analytics platform, Tableau, for data visualization. Users could modify the data by selecting a specific date range, time window, work shift, institution(s), specific test(s), and/or testing platform(s). Access was controlled by OKTA integration to the host server over the web, behind the hospital firewall. During the April 2020 surge, we saw an increase in blood gas testing and corresponding decrease in non-critical testing such as Vitamin D. At our institution, SARS-CoV-2 molecular testing was performed using four primary platforms, four in-house and one send-out. Weekly and hourly testing volumes as well as turnaround times fluctuated based on reagent availability, new testing requests, staffing, and operational changes. Productivity dashboards indicated that coagulation testing volumes were highest on the third shift and that all three analyzers may not be necessary. Further, specimen volumes and productivity of accessioning staff varied throughout the day. Phlebotomy venipuncture volumes and patient wait times also varied throughout the pandemic. A decrease in ambulatory draws was seen during the surge but after reopening draw volumes, particularly at offsite locations, surpassed prepandemic volumes. We demonstrate that data analytics and interactive dashboards are powerful tools, are helpful in response to a pandemic and lead to improved TAT, supply utilization, staffing and workflows. Furthermore, dashboards provide objective data to review with hospital leadership and promote collaboration.

Hemolysis Index and Potassium Reporting.

OBJECTIVES: In vitro hemolysis generates a spurious increase in potassium. Roche Diagnostics recently revised its recommended guidelines for potassium reporting on cobas analyzers. By dramatically reducing the allowable degree of hemolysis, these guidelines would increase specimen rejection rates. We attempted to balance the desire to avoid inaccurate results with the clinical implications of increased specimen rejection rates. METHODS: We downloaded hemolytic indices (HI) for 80,795 specimens tested at our institution on cobas chemistry analyzers in 1 month and evaluated potential specimen rejection rates based on the new criteria. We also spiked nonhemolyzed samples with hemolyzed blood to assess the influence of HI values on potassium measurements. RESULTS: The new recommendations would lead to specimen rejection rates of 76% in the neonatal intensive care unit (NICU), 41% in the emergency department (ED), 16% in inpatient specimens, and 9% in outpatient samples. Our current criteria of reporting potassium concentrations in inpatient and outpatient specimens with HI ≤100 and in NICU and ED specimens with HI ≤300 and additional interpretive guidance for HI values between 100 and 300 reduce unnecessary specimen rejections to 3% in NICU, 2% in ED and inpatients, and less than 1% in outpatients without significantly increasing the number of clinically consequential incorrect results. CONCLUSIONS: The new recommendations would lead to unacceptably high specimen rejection rates. Laboratories should develop context-specific, evidence-based reporting criteria that minimize reporting of inaccurate results without disrupting delivery of care.

Significant Operational Improvements with Implementation of Next Generation Laboratory Automation.

OBJECTIVES: To investigate the benefits and challenges of introducing next generation chemistry and coagulation automation. METHODS: We replaced the Roche modular preanalytic system attached to Roche Cobas 6000 analyzers with the Roche 8100 preanalytical line attached to the Roche Cobas 8000 and Stago STA R Max analyzers. The system included 2 add-on buffers (AOBs) for automated specimen archival and retrieval and primary-tube specimen processing. We measured turnaround time (TAT) from specimen receipt to result for chemistry and coagulation tests before, during, and after system implementation. TAT for add-on tests was also measured. RESULTS: We completed the system implementation during a 17-month period using existing laboratory space. The TAT for chemistry, coagulation, and add-on tests decreased significantly (P <.005, P <.001, and P <.005, respectively). We encountered several challenges, including barcode-label errors, mechanical problems, and workflow issues due to lack of bidirectional track for coagulation testing. CONCLUSIONS: Next generation laboratory automation yielded significantly shortened and less-variable TAT, particularly for add-on testing. Our approach could help other laboratories in the process of implementing and configuring automated systems.

The Role of GDF-15 in Heart Failure Patients With Chronic Kidney Disease.

BACKGROUND: Growth differentiation factor-15 (GDF-15) is a stress-inducible cytokine and member of the transforming growth factor-ß cytokine superfamily that refines prognostic assessment in subgroups of patients with heart failure (HF). We evaluated its role in HF patients with chronic kidney disease (CKD, estimated glomerular filtration rate <60 mL/min/1.73 m2). METHODS: A total of 358 patients with stable systolic HF were followed for a median of 1121 (interquartile range, 379-2600) days. Comprehensive evaluation including B-type natriuretic peptide (BNP) and GDF-15 testing was performed at study entry; the analysis was stratified according to kidney function. RESULTS: Patients with CKD (33.8%) were older, had more often diabetes, and were less often treated with angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARB). GDF-15 was associated with estimated glomerular filtration rate, whereas BNP was associated with left ventricular-end diastolic diameter and ejection fraction (P < 0.01). During follow-up, 244 patients (68.2%) experienced an adverse outcome (death, urgent transplantation, implantation of mechanical circulatory support). In patients with HF and CKD, the Cox proportional hazard model identified BNP, GDF-15, sex, systolic blood pressure, sodium, total cholesterol, and ACEi/ARB treatment as significant variables associated with an adverse outcome (P < 0.05). In multivariable analysis, BNP was replaced by GDF-15. Net reclassification improvement confirmed prognostic superiority of the model encompassing GDF-15 (GDF-15, sodium, total cholesterol, ACEi/ARB treatment) compared with the model without GDF-15 (BNP, sex, sodium, ACEi/ARB treatment), net reclassification improvement 0.62, P = 0.005. In contrast, in patients with HF and normal kidney function, BNP remained superior to GDF-15 in a multivariable model. CONCLUSIONS: In patients with systolic HF and CKD, GDF-15 is more strongly associated with adverse outcomes than the conventionally used BNP.

B-Type Natriuretic Peptide and Cardiac Troponin I Are Associated With Adverse Outcomes in Stable Kidney Transplant Recipients.

BACKGROUND: Approximately 200 000 kidney transplant recipients are living in the United States; they are at increased risk for cardiovascular and other adverse outcomes. Biomarkers predicting these outcomes are needed. Using specimens collected during the Folic Acid for Vascular Outcome Reduction in Transplantation trial, we determined whether plasma levels of B-type natriuretic peptide (BNP) and cardiac troponin I are associated with adverse outcomes in stable kidney transplant recipients. METHODS: Five hundred ten subjects were selected randomly from the 4110 Folic Acid for Vascular Outcome Reduction in Transplantation participants. This cohort was then enriched for all additional subjects with adverse outcomes (death, dialysis-dependent kidney failure (DDKF), and cardiovascular outcomes) for a total of 1131 participants studied. Quartiles of BNP and high-sensitivity cardiac troponin I (hs-cTnI) were included in adjusted models. Combinations of normal and elevated hs-cTnI (>26.2 ng/L) and BNP (>100 pg/mL) were also studied. RESULTS: Median concentrations (interquartile ranges) were 5.6 (3.3-10.5) ng/L for hs-cTnI and 39 (15, 94) pg/mL for BNP. Hazard ratios for each adverse outcome were higher with higher quartiles of BNP after adjustment and remained statistically significant after adding hs-cTnI to the model. The highest quartile hazard ratio for DDKF was 2.47 (95% confidence interval [95% CI], 1.21-5.05). Simultaneous elevations of BNP and hs-cTnI over clinical cutoffs were strongly associated with adverse outcomes with hazard ratios 8.8 (95% CI, 3.4-23.1) for DDKF and 6.3 (95% CI, 2.7-15.0) for cardiovascular outcomes. CONCLUSIONS: Higher BNP is associated with mortality and cardiovascular and kidney outcomes in stable kidney transplant recipients. Elevated BNP and hs-cTnI identify candidates for targeted risk reduction.

Early release of high-sensitive cardiac troponin during complex catheter ablation for ventricular tachycardia and atrial fibrillation.

BACKGROUND: Radiofrequency ablation results in intentional cardiac injury. We aimed to assess the kinetics of cardiac injury as measured by cardiac troponin release following ventricular ablation and atrial ablation. METHODS: Patients undergoing ablation for ventricular tachycardia (VT) with structural heart disease (19 patients) or atrial fibrillation (AF, 24 patients) were prospectively enrolled. High-sensitivity cardiac troponin T (hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI) were measured before ablation as well as 30 min, 60 min, 90 min, 120 min, 4 h, 8 h, and 24 h after applying the first ablation lesion. RESULTS: Median ablation time, power used, and energy delivered were 28 min, 39 W, and 69,713 J in VT ablations and 55 min, 29 W, and 95,425 J in AF ablations, respectively. Release of hs-cTnT occurred promptly with both, but reached greater levels earlier for ventricular compared to atrial ablation (hs-cTnT after 30 min 191 vs. 31 ng/l, after 1 h 467 vs. 80 ng/l; hs-cTnI after 30 min 132 vs. 30 ng/l, after 1 h 331 vs. 76 ng/l; p < 0.001 for all comparisons). After 24 h, levels were similar (hs-cTnT 1325 vs. 1303 ng/l, p = 0.92; hs-cTnI 2165 vs. 1996 ng/l, p = 0.55). Levels of hs-cTnT after 24 h correlated well with the energy delivered in AF ablations (r = 0.81 and r = 0.75, p < 0.001), but not in VT ablations (r = 0.35 and r = 0.44, p = ns). CONCLUSIONS: Evidence of cardiac injury as indicated by the release of hs-cTnT and hs-cTnI occurs early with atrial and ventricular ablation. Higher early levels are observed in ventricular ablations, but levels are similar after 24 h. The extent of total troponin release seems to correlate well with the amount of energy delivered in AF ablations, but not in VT ablations.

Fully automated ultrasensitive digital immunoassay for cardiac troponin I based on single molecule array technology.

BACKGROUND: The association between increases in cardiac troponin and adverse cardiac outcomes is well established. There is a growing interest in exploring routine cardiac troponin monitoring as a potential early indicator of adverse heart health trends. Prognostic use of cardiac troponin measurements requires an assay with very high sensitivity and outstanding analytical performance. We report development and preliminary validation of an investigational assay meeting these requirements and demonstrate its applicability to cohorts of healthy individuals and patients with heart failure. METHODS: On the basis of single molecule array technology, we developed a 45-min immunoassay for cardiac troponin I (cTnI) for use on a novel, fully automated digital analyzer. We characterized its analytical performance and measured cTnI in healthy individuals and heart failure patients in a preliminary study of assay analytical efficacy. RESULTS: The assay exhibited a limit of detection of 0.01 ng/L, a limit of quantification of 0.08 ng/L, and a total CV of 10% at 2.0 ng/L. cTnI concentrations were well above the assay limit of detection for all samples tested, including samples from healthy individuals. cTnI was significantly higher in heart failure patients, and exhibited increasing median and interquartile concentrations with increasing New York Heart Association classification of heart failure severity. CONCLUSIONS: The robust 2-log increase in sensitivity relative to contemporary high-sensitivity cardiac troponin immunoassays, combined with full automation, make this assay suitable for exploring cTnI concentrations in cohorts of healthy individuals and for the potential prognostic application of serial cardiac troponin measurements in both apparently healthy and diseased individuals.

Prognostic implications of low level cardiac troponin elevation using high-sensitivity cardiac troponin T.

BACKGROUND: High-sensitivity cardiac troponin T (hsTnT) is used in many countries, but is not available in the United States. Prior evidence has been viewed as inconclusive as to whether low cardiac troponin T (cTnT) concentrations detected with hsTnT are prognostically meaningful compared with fourth-generation cTnT. HYPOTHESIS: The aim of this study was to assess the prognostic performance of low-level cTnT elevations using the hsTnT assay compared with the assay (fourth-generation) currently available in the United States. METHODS: We measured serum cTnT in 4160 patients with non-ST-elevation acute coronary syndrome using both the hsTnT and fourth-generation assays. Patients were stratified at the 99th percentile cut point for each assay. RESULTS: Patients with baseline hsTnT ≥14 ng/L (n = 3697) vs <14 ng/L were at higher 30-day risk of cardiovascular death (CVD) or myocardial infarction (MI) (9.1% vs 1.9%, P < 0.0001). After adjusting for all other elements of the Thrombolysis In Myocardial Infarction risk score, hsTnT ≥14 carried a 5.2-fold higher risk of CVD/MI (95% confidence interval [CI]: 2.6-10.1, P < 0.0001). Low levels of hsTnT (14-50 ng/L) also revealed increased risk (CVD/MI: 6.4%, P = 0.002). Importantly, patients with negative fourth-generation cTnT but positive hsTnT were at 4.5-times higher risk of CVD/MI (95% CI: 1.9-11.0, P = 0.0008) than patients with negative hsTnT. In contrast, patients with a negative hsTnT but positive fourth-generation cTnT result had a lower rate of CVD/MI than with a positive hsTnT (1.3% vs 8.2%, P = 0.0005). CONCLUSIONS: Low-level increases in cTnT detected using the hsTnT assay identified patients at a meaningfully higher risk and who might otherwise be missed, and improves upon risk stratification using the cTnT assay currently available in the United States.

Prognostic performance of a high-sensitivity assay for cardiac troponin I after non-ST elevation acute coronary syndrome: Analysis from MERLIN-TIMI 36.

BACKGROUND: Newer troponin assays offer the ability to quantify circulating troponin levels at an order of magnitude lower than contemporary assays, fueling continued debate over the prognostic implications of very low-level increases in concentration. We evaluated the prognostic implications of low-level increases in cardiac troponin I (cTnI) using an investigational single-molecule high-sensitivity assay in patients with acute coronary syndrome (ACS). METHODS: We measured cTnI using both a high-sensitivity troponin I (hsTnI) assay (Erenna, Singulex, 99(th) percentile 9 pg/ml) and a current generation sensitive assay (TnI-Ultra, Siemens, 99(th) percentile 40 pg/ml) at baseline in 1807 patients with non-ST elevation ACS and compared their prognostic ability for adverse cardiovascular events at 30 days and one year. RESULTS: Among patients with TnI-Ultra<99(th) percentile, patients with elevated hsTnI (≥ 9 pg/ml) had a significantly higher risk than patients with hsTnI<9 pg/ml: cardiovascular death (CVD) or myocardial infarction (MI) at one year (7.0% vs 3.8%; p<0.001, hazard ratio (HR) 2.05, confidence interval (CI) 1.23-3.41); including a higher risk of CVD (3.5% vs 1.5%, p<0.001) and MI (5.0% vs 2.8%, p<0.001) individually. This higher risk of CVD/MI was independent of clinical risk stratification using the TIMI Risk Score (adj. HR 1.76, CI 1.05-2.90). Moreover, hsTnI showed a trend toward a gradient of risk even below the hsTnI 99 percentile. CONCLUSIONS: Low-level cardiac troponin detected using a single-molecule technique, below the cutpoint of a contemporary sensitive assay, identified a significant gradient of risk. These findings support the prognostic relevance of low-level cardiac troponin elevation with increasingly sensitive assays in patients with ACS.

Cardiac troponins and high-sensitivity cardiac troponin assays.

Measurement of circulating cardiac troponins I and T has become integral to the diagnosis of myocardial infarction. This article discusses the structure and function of the troponin complex and the release of cardiac troponin molecules from the injured cardiomyocyte into the circulation. An overview of current cardiac troponin assays and their classification according to sensitivity is presented. The diagnostic criteria, role, and usefulness of cardiac troponin for myocardial infarction are discussed. In addition, several examples are given of the usefulness of high-sensitivity cardiac troponin assays for short-term and long-term prediction of adverse events.

Evaluation of the diagnostic performance of current and next-generation assays for cardiac troponin I in the BWH-TIMI ED Chest Pain Study.

BACKGROUND: Rapid diagnosis of acute coronary syndrome is a clinical and operational priority in busy emergency departments (ED). We examined the performance of an investigational troponin I (TnI) assay with 10-100-times greater sensitivity than current commercial assays. METHODS: Among patients with non-traumatic chest pain enrolled in the BWH-TIMI ED Chest Pain Study, we measured TnI (n=381) at baseline, 4-6 h, and 12-24 h with an investigational assay (S-TnI; Singulex, detection-limit 0.0002 µg/l, 99th percentile 0.009 µg/l) and a contemporary sensitive assay (TnI-Ultra; Siemens, detection-limit 0.006 µg/l, 99th percentile 0.04 µg/l). Final diagnosis was adjudicated using all diagnostic data and local hospital-based cardiac TnI (Siemens), blinded to investigational cardiac Tn. RESULTS: The adjudicated diagnosis was myocardial infarction (MI) in 96 patients, unstable angina in 41, and acute non-coronary cardiovascular conditions in 50 patients. Baseline S-TnI was highly sensitive for MI (97%, 95% CI 91-99%) with specificity 81% (95% CI 76-86%) and positive predictive value 63% (95% CI 55-71%). The negative predictive value with S-TnI was 99% (95% CI 96-100%). S-TnI had better diagnostic accuracy than the local assay (area under the curve 0.976 vs. 0.916, p=0.003). Among 20 patients with negative baseline TnI and diagnosis of MI, 19 had elevated baseline S-TnI. Compared to TnI-Ultra, S-TnI trended toward higher sensitivity (97 vs. 94%, p=NS) but did not differ significantly in negative predictive value (99 vs. 98%) or area under the curve (p=0.29). CONCLUSION: Current and investigational Tn assays substantially increased clinical sensitivity and improved diagnostic accuracy for MI, despite a decline in specificity. A contemporary sensitive assay delivered similar overall accuracy to the investigational test, suggesting that we have reached a point of maximum diagnostic return with increasing analytical sensitivity.

Evaluation of the diagnostic performance of heart-type fatty acid binding protein in the BWH-TIMI ED chest pain study.

Chest pain is one of the most common reasons for presentation to the Emergency Department and the ability to rapidly and correctly diagnose the minority of patients who have a myocardial infarction is of critical importance. We assessed the diagnostic performance of a multimarker strategy using heart-type fatty acid binding protein (H-FABP) in combination with a contemporary sensitive troponin (cTn) assay. We measured H-FABP (Randox) and a sensitive cTn (TnI-Ultra, Siemens) at baseline in 343 patients with chest pain enrolled in the prospective BWH-TIMI ED chest pain study. Final presenting diagnosis was adjudicated using all diagnostic data, including the local cTnI results, but reviewers were blinded to H-FABP and the sensitive cTn assays. The diagnostic accuracy of H-FABP and local cTn together (AUC 0.962) was superior to local cTn alone (AUC 0.910, p = 0.0009) with an especially marked improvement in early presenters (AUC 0.983 vs. 0.840, p = 0.0098). In contrast, when combined with the sensitive cTn assay, there was no significant difference in the AUC with H-FABP as compared with the sensitive cTn alone, either in the overall cohort (AUC 0.963 vs. 0.956, p = 0.23) or in early presenters (AUC 0.999 for both). In early presenters, the addition of H-FABP resulted in a NPV of 100% when combined with either the local or sensitive cTn assay. In our study, the addition of H-FABP significantly enhanced the sensitivity and accuracy of diagnosis as compared to a prior-generation troponin assay alone, especially in patients who presented early. H-FABP but did improve overall diagnostic accuracy when added to a current-generation sensitive troponin assay; however, their combination offered the best NPV in early presenters. Further studies are needed to determine the utility a very rapid "rule out" of MI with a single blood draw of troponin and H-FABP at presentation.

Implementation of a highly sensitive cardiac troponin I assay: test volumes, positivity rates and interpretation of results.

BACKGROUND: While more sensitive cardiac troponin (cTn) assays may overcome current limitations in diagnosing acute coronary syndrome (ACS), clinicians and laboratorians are concerned about the clinical impact of higher rates of cTn positivity. METHODS: We collected statistics on test volume and positivity rates before and after the implementation of a more sensitive assay. We divided patients into 6 groups based on their cardiac troponin I (cTnI) results and utilized additional laboratory test results to determine the impact of the new assay. In addition, we assessed the clinical significance of low-positive cTnI results (0.05-0.10 microg/l). RESULTS: Lowering the diagnostic cutoff from 0.10 to 0.04 microg/l increased the number of positive test results by 44.2% hospital-wide and 114.4% in the emergency department without significantly changing test volume. In some patients, low-positive results were part of the typical rise and fall of cTnI consistent with myocardial damage. Diagnosis was more challenging in patients with consistently low-positive results. Patients in this group were significantly more likely to have impaired renal function than those with cTnI elevations >0.10 microg/l. CONCLUSIONS: More sensitive cTn assays will increase the number of positive results and allow for earlier detection of cardiac injury while also detecting non-ACS related pathologies.