University of Edinburgh

British Heart Foundation

DL-2021-031

When the heart is damaged troponin is being released in the bloodstream. High-sensitivity troponin tests measure the troponin level in the blood and are the preferred choice for the diagnosis of a heart attack. In clinical practice either a high-sensitivity troponin I or T test is being used. They are both recommended in current guidelines, but limited data is available about the agreement between the diagnostic cut offs of high-sensitivity troponin I and T. NHS Lothian hospitals are scheduled to change from a high-sensitivity troponin I to a T test. As part of this process, it is standard laboratory practice for NHS Lothian to verify the performance of the new test. Therefore, we will evaluate in patients who present at the Emergency Department with a suspicion of a heart attack whether the diagnostic cut offs of troponin I and T will identify the same patients for having a heart attack.

Cardiac troponin is central to the diagnosis of myocardial infarction and high-sensitivity cardiac troponin assays (hs-cTn) are the preferred choice for the assessment of patients with suspected acute coronary syndrome. The 99th percentile upper reference limits of hs-cTn derived from a healthy reference population is the recommended diagnostic threshold for myocardial infarction. Since the introduction of hs-cTn assays in Europe in 2010, most hospitals have switched from contemporary sensitive cardiac troponin assays to a hs-cTn assay. The current guidelines state that high-sensitivity cardiac troponin I (hs-cTnI) and T (hs-cTnT) assays have similar performance and are clinically interchangeable. Although both hs-cTnI and hs-cTnT assays are recommended in current guidelines, limited data is available on the discordance of diagnostic thresholds of hs-cTnI and hs-cTnT for ruling-in and ruling-out myocardial infarction in consecutive patients with suspected coronary syndrome. It is increasingly recognised that hs-cTn assays can be vulnerable to interference from circulating antibodies. Repeating the test on another hs-cTn assay may allow identification of this interference where the two results are highly discordant. Clinical research studies occasionally utilise different troponin assays at different sites for practical reasons. The extent to which differences between hs-cTnI and hs-cTnT assays affect comparisons between results is uncertain. NHS Lothian hospitals (the Royal Infirmary of Edinburgh, Western General Hospital and St John’s Hospital) are scheduled to change from a hs-cTnI assay to a hs-cTnT assay. As part of this process, it is standard laboratory practice for NHS Lothian to verify the performance of the new assay by using patient samples to compare results from the hs-cTnT assay to the existing hs-cTnI assay.

Public Health Research

22/02/2022

De-Personalised

TRE