Association of a Novel Protocol for Rapid Exclusion of Myocardial Infarction With Resource Use in a US Safety Net Hospital.

Importance: High-sensitivity cardiac troponin T (hs-cTnT) protocols for the evaluation of chest pain in the emergency department (ED) may reduce unnecessary resource use and overcrowding. Objective: To determine whether the implementation of a novel hs-cTnT protocol, which incorporated troponin values drawn at 0, 1, and 3 hours after ED presentation and the modified HEART score (history, electrocardiogram, age, risk factors), was associated with improvements in resource use while maintaining safety. Design, Setting, and Participants: This retrospective cohort study from Parkland Health and Hospital System, a large safety net hospital in Dallas, Texas, included data on 31 543 unique ED encounters in which patients underwent electrocardiographic and troponin testing from January 1, 2017, to October 16, 2018. The hs-cTnT protocol was implemented in December 2017. Main Outcomes and Measures: Resource use outcomes included trends in ED dwell time, troponin to disposition decision time (the difference between the first troponin draw time and the time an order was placed for inpatient admission, admission to observation, or discharge), and final patient disposition. Safety outcomes included readmission for myocardial infarction and death. Results: In 31 543 encounters, mean (SD) patient age was 54 (14.4) years and 14 675 patients (48%) were female. Department dwell time decreased by a mean of -1.09 (95% CI, -2.81 to 0.64) minutes per month in the preintervention period. The decline was steeper after the intervention (-4.69 [95% CI, -9.05 to -0.33] minutes per month) (P for interaction = .007). The troponin to disposition time was increasing in the preintervention period by 1.72 (95% CI, 1.08 to 2.36) minutes per month; postintervention, the mean difference increased more slowly (0.37 [95% CI, -1.25 to 1.99 minutes per month; P value for interaction = .007]). The proportion of patients discharged from the ED increased after the intervention (48% vs 54%, P < .001). Thirty-day major adverse cardiac event rates were low and did not differ before and after the intervention. Conclusions and Relevance: Implementation of a novel protocol incorporating serial hs-cTnT measurements over 3 hours with the Modified HEART Score was associated with reduction in ED dwell times and attenuation of temporal increases in time from troponin measurement to disposition. This or similar protocols to rule out myocardial infarction have the potential to reduce ED overcrowding and improve health care quality while maintaining safety.

Validation and implementation of the fifth-generation high sensitivity Troponin T (hs-TnT) assay at a large teaching county hospital. A laboratory-driven multi-speciality effort.

We describe the validation and implementation of the new 5th generation high sensitivity Troponin T assay (Roche Diagnostics®). In addition to the assay improved sensitivity, the numerical values, reporting units, reference intervals, and critical limits are markedly different. We describe the use of clinical correlation as the basis for implementation and validation of the fifth-generation hs-TnT assay at a large teaching county hospital.

Plasma lactate measurement as an example of encountered gaps between routine clinical laboratory processes and manufactures' sample-handling instructions.

OBJECTIVES: Deviation from manufacturers' pre-analytical sample handling recommendations necessitates extensive validation studies. This report uses plasma lactate testing, where a recommended 15 min room temperature sample handling limit cannot be met by the clinical laboratory, as an example for studies to bridge the gap with practice. DESIGN AND METHODS: Triplicate blood samples were collected from patients (n = 51) with lactate requests by clinicians and from normal volunteers (n = 50). One tube was transported on ice (4 °C), the others were maintained at room temperature (23 °C). Tubes stored at 4 °C were processed at 30 min from collection. Tubes stored at 23 °C were processed at 15 and at 30 min from collection. Lactate levels were measured using Roche Diagnostics Cobas 6000® analyzer. RESULTS: Lactate levels in normal subjects ranged from 0.6 to 3.1 mmol/L (median 1.1). Patient lactate levels ranged from 0.8 to 26.3 mmol/L (median 2.2). Bias in lactate levels following extended storage of samples from both normal subjects and patients ranged from - 1.3 to2.2 and from - 1.0-1.0 mmol/L when stored for 30 min at 23 °C or at 4 °C, respectively. The bias between lactate levels at 30 min at 23 °C and 4 °C was - 1.2 to - 0.5 mmol/L for both populations. Although the bias was not statistically significant for all variables, a clinically significant (>0.2 mmol/L) bias was observed in 28% of normal and 7.0% of patient samples. CONCLUSION: Extending the pre-analytical time to 30 min at 23 °C did not significantly impact clinical utility of lactate measurement in our patient population.