Sample collection time and sample handling are important for cardiac markers. Blood samples should be collected and assayed in intervals. ESC/ACC guidelines stress the importance of serial sampling. They recommend sampling at the presentation of chest pain (baseline), then at 6 – 9 hours, and if these samples are negative and necrosis is still suspected, repeat testing at 12 – 24 hours. Other studies recommend sampling at presentation, 2 – 4 hours, 6 – 8 hours, and at 12 hours.
The image displayed from ESC shows a rule-out and rule-in algorithm for high-sensitivity troponin assays in which patients are classified into one of three pathways dependent on the hsTn results at baseline and 1 hour or 2 hours later.3
Many laboratories will have serial troponin testing orderable as a panel (baseline, 30 min, 1 hour, 2 hours, etc.)
Troponin measurement should be available 24 hours a day and the results presented within 30 – 60 minutes after sample collection.
Point-of-care troponin testing is available that uses whole blood samples. Most large laboratories will also have larger instruments that perform plasma testing, these are typically more precise.
When using plasma, proper centrifugation is critical as small clots or debris are known to cause false-positive troponin results on some platforms. Once centrifuged, samples should be handled with care to avoid resuspension of any particulate matter that can interfere with the assay.
3. European Society of Cardiology. "2023 ESC Guidelines for the management of acute coronary syndromes: Developed by the task force on the management of acute coronary syndromes of the European Society of Cardiology (ESC)." Eur Heart J, Volume 44, Issue 38, 7 Oct 2023, pages 3720–3826, https://doi.org/10.1093/eurheartj/ehad191.
