Clinical Significance of Serum Cardiac Troponin I Measurements Less Than The 99th Percentile

Troponins are a group of proteins found in both skeletal and cardiac muscle fibers that control muscle contraction. Cardiac troponin (cTn) tests measure the level of cardiac specific troponins, either cTnI or cTnT, present in the blood that are released in response to myocardial damage. Standard treatment for patients with a concern for cardiac compromise includes drawing a cTn initially, and then repeating the test at 3 hours with additional trending as necessary. At UVMMC, the cTnI assay currently used (Ortho Clinical Diagnostics Vitros 5600) is able to detect cTnI as low as 0.012 ng/mL. Although this data is available, it is not reported to the medical provider as any value \u3c0.034 ng/mL is reported to the provider as “\u3c0.034 ng/mL”. The cTnI value of 0.034 ng/mL represents the level of cTnI that is detectable in 99% of the population measured by this assay. This value is important in that under the 4th universal definition of myocardial infarction, a patient must have a cTn value above this set point to meet the definition for myocardial infarction. Given this information, when the current cTnI assay was adopted at UVMMC a decision was made by cardiology and the laboratory to mask all cTnI results \u3c0.034 ng/mL as the clinical significance of those values was in question. Objectives: Primary Objective: Review unblinded cTnI results in ED patients at UVMMC to determine if blinding the providers to cTnI values of \u3c0.034 ng/mL resulted in adverse patient outcomes. Secondary Objective: Determine if the current practice of blinding providers to cTnI values \u3c0.034 ng/mL should continue and this practice be acceptable to expand to the UVMHN. Methods: The Department of Pathology and Laboratory Medicine has a record of all troponins resulted at UVMMC, with their precise values (beginning at 0.012 ng/mL). This study proposes utilizing this data set to identify medical records in EPIC to be assessed to evaluate if blinding the providers to cTnI values of \u3c0.034 ng/mL resulted in adverse patient outcomes. Results: Currently reviewing 402 records for primary diagnosis, secondary diagnoses, ICU admission, admission diagnosis, admission dates, principal procedure, secondary procedure(s), length of hospital stay, discharge disposition, readmission within 30 days, and outpatient follow-up to see if unblended cTnl results in ED patients at UVMMC resulted in an adverse patient outcome. Conclusion: Determine if current practice of blinding providers to cTnl values of \u3c0.034 ng/mL is a safe practice for patients or if unblinding should be adopted in UVMHN and become standard of care