The TIGER study is a study investigating the utlility of a point-of-care blood analyse of Troponin I to help identify patients with heart attacks in the prehospital emergency care. The study is conducted within the ambulance services of Region Stockholm and compares standard medical care with and without the addition of this quick test. Chest pain is one of the most common reasons for ambulance dispatch, but currently only about one-third of heart attacks are detected before arriving at the hospital-mainly through ECG. The remaining two-thirds are not identified until after further testing at the emergency department. The TIGER study aims to improve early diagnosis by using a high-sensitivity, point-of-care Troponin I test already in the prehospital phase. The study is a randomized controlled trial, where participants are randomly assigned to one of two groups. One group receives standard emergency care along with the rapid Troponin I test in the ambulance. The other group receives standard care without the test. The goal is to evaluate whether the use of Troponin I testing leads to faster and more accurate identification of heart attacks, ultimately improving patient outcomes. In total, about 1,419 adult patients with chest pain or suspected heart attack will participate. The primary outcome being measured is the time from first medical contact to PCI (balloon angioplasty). Secondary outcomes include time spent in different parts of care, hospital length of stay, the occurrence of serious events (such as heart attack, stroke, or death), and the diagnostic accuracy of the test. The study has been approved by the Swedish Ethical Review Authority and includes safety monitoring through an interim analysis after the first 150 patients. Test results from the Troponin I analysis are clearly marked as part of the research study and should be interpreted by the responsible physician alongside other clinical findings.