Troponin Timing Trouble: Real-World Performance of a 1- and 3-Hour Algorithm

Emergency departments in the United States have transitioned to high-sensitivity troponin assays over the past decade. Initial re-testing algorithms balanced safe care for a high-risk condition and operational efficiency in busy departments, with many choosing a more conservative approach to a new tool. The most popular algorithms involve a repeat either one or two hours after the initial test. We present pathway adherence data for a combined 1- and 3-hour repeat high-sensitivity troponin algorithm in an urban, academic health system.

We retrospectively analyzed high-sensitivity troponin testing in five urban emergency departments from the same academic health system from Jan 2021 – Dec 2024. For each encounter in which a patient had a troponin ordered, we analyzed adherence to the health system’s pathway, which calls for 1-hour repeats for troponins greater than 5ng/dL, and 3-hour repeats for 1-hour deltas greater than 1ng/dL.

180,200 encounters met inclusion criteria, involving 96,920 unique patients and accounting for over 320,000 high-sensitivity troponin tests. A repeat troponin was indicated in 41.50% (74,779); 72.44% (54,170) of these were completed (p<0.0001). The median time to collect the repeat test was 130 minutes [IQR 82, 211]. Of those requiring a 1-hour repeat, 59.13% (44,220) had a change in troponin significant enough to prompt a 3-hour repeat. Only 51.90% (22,948) of these 3-hour tests were ordered and collected (p<0.0001). The median time to collect the 2nd repeat was 320 minutes [IQR 196, 669].

The pathway being evaluated has multiple downfalls. For one, a large proportion of patients require a 3-hour test, removing much of the theoretical early-disposition value of a 1-hour repeat. Overall, adherence is poor to this algorithm, both in terms of re-ordering and collection timing. Future directions for improvement could include re-evaluation of the discharge parameters or exploring a switch to a 2-hour pathway.