Short Attention Span Summary
hs-cTnT and hs-cTnI are not the same!
This was a meta-analysis of 11 cohort studies, over 9000 patients, doing rapid MI rule out with non-ischemic ECG and negative single hs-cTnT. They found the pooled sensitivity for MI was 98% and 98.7% for MACE.
This is the same assay just approved in the US - hs-cTnT. It is different than hs-cTnI, as an EM Topics reader pointed out in an email last month. Craig Davidson, Consultant in EM, Edinburgh noted, "As I understand it the hs-cTnI test is more accurate and able to detect smaller changes in trop than hs-cTnT. The single test rule out strategy is better with hs-cTnI than the hs-cTnT test (quoted with permission)."
He's right, according to an open-access EHJ comparison study. The high sensitivity troponin I appears better than T for early presenters. "In early presenters (<3 h since chest pain onset) hs-cTnI showed a higher diagnostic accuracy when compared with hs-cTnT, while hs-cTnT was superior in late presenters vs. hs-cTnI."
In this collection of studies, a non-ischemic ECG and single hs-cTnT performed well. Use caution with hs-cTnT in patients presenting with symptoms < 3 hours.
Your comments and emails matter to me and to your colleagues. Thank you, and keep them coming!
Rapid Rule-out of Acute Myocardial Infarction With a Single High-Sensitivity Cardiac Troponin T Measurement Below the Limit of Detection: A Collaborative Meta-analysis. Ann Intern Med. 2017 Apr 18. doi: 10.7326/M16-2562. [Epub ahead of print]
Read the EHJ comparison study in full text.