Cost-effectiveness of cardiac troponin I in a systematic chest pain evaluation protocol: use of cardiac troponin I lowers length of stay for low-risk cardiac patients.

We evaluated several measures of clinical and fiscal interest to assess the effect of adding an automated cardiac troponin I (c-TnI) assay to our current cardiac panel, which consists of creatine kinase MB (CK-MB), myoglobin, total CK activity, and a calculated CK-MB relative index. Samples were collected on admission and at 3, 6, and 8 hours after admission as part of our diagnostic protocol. Our study was designed to collect data on a control group of patients, implement a change (i.e., c-TnI testing), and then measure the effect of the change on a test population having otherwise equivalent diagnostic and therapeutic pathways. We assessed differences in patient hospital and cardiac care unit length of stay (LOS), time to cardiac catheterization, and hospital and laboratory charges and costs. We found that adding c-TnI to our testing regimen decreased LOS for the large test population. Within this large test population, patients classified as low risk for acute myocardial infarction experienced statistically and clinically significant shorter LOS and lower total and variable hospital costs; for patients with unstable angina, there was an increase (though not statistically significant) in laboratory costs.