Our high-sensitivity troponin comes out in ng/L, and doesn't give us numbers after a decimal point. i.e.
<6 is the lowest possible reading, and from there 7, 8, 9, 40, you get the idea.
We have an algorithm we generally adhere to with the expectation that we generally do at least one repeat unless HPI dictates otherwise. On the second troponin, a delta of <4 is considered insignificant, and you can stop there. Delta of 4 - 9 warrants a third troponin. 10 or greater and it's generally admit, call cardiology time.
Cardiac biomarkers of acute coronary syndrome: from history to high-sensitivity cardiac troponin - PubMed
This is the paper referenced to justify the algorithm.