During a heart attack, the protein troponin I is released from the heart muscle into the bloodstream. Measurements of cardiac troponin in blood are used as an aid in the diagnosis of heart attack. Low levels of troponin are also present in the blood stream of healthy individuals and can be detected by high-sensitive troponin tests. The SpinChip hs-cTnI test is a new high-sensitive test for measuring the amount of cardiac troponin I in the bloodstream as an aid in the diagnosis of heart attack.

The purpose of this study is to determine the upper reference limits (URLs) for the SpinChip hs-cTnI test in a healthy population.

Cardiac troponins are widely used as a biomarker to aid in the diagnosis of Acute myocardial infarction (AMI). These structural proteins are essential in regulating contraction in cardiac muscle cells, and they are sensitive and specific biochemical markers of myocardial damage.

During a heart attack, cardiac muscle cells are injured and release the cardiac marker troponin I (cTnI) into the bloodstream. High-sensitive troponin tests may detect the increase of cardiac troponin in blood within hours after the symptoms of a heart attack has started.

According to the European Society of Cardiology (ESC) 2023 guideline for acute coronary syndrome (ACS) in patients presenting without persistent ST-segment elevation, an elevated cTn value above the 99th percentile upper reference limit (URL) indicates myocardial injury, and when accompanied by evidence of acute myocardial ischemia, the disease is defined as AMI. The diagnostic threshold (99th percentile URL) for each hs-cTn test method must be specifically established.

The SpinChip high-sensitivity cardiac troponin I (hs-cTnI) test is a new high-sensitive test for measuring troponin I in blood samples, and the analysis may be performed close to the patient (near-patient test). The results may be obtained within 10 minutes, compared to approximately 1 hour for normal laboratory analysis using fresh venous whole blood and plasma samples.

The SpinChip Platform consists of the SpinChip hs-cTnI test and the SpinChip Analyzer and may be used at the emergency department to evaluate patients presenting with symptoms of acute myocardial infarction (chest pain). The test can use blood from finger prick or venous blood samples, either as whole blood or separated into plasma.

This study is a multicentre, prospective, observational, non-randomised, clinical performance study in healthy subjects to determine the 99th percentile URLs for the SpinChip hs-cTnI test according to recommendations from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC).

Inclusion Criteria:

• Able and willing to provide signed written informed consent
• 18-80 years old
• Estimated glomerular filtration rate (eGFR) > 60 mL/min/1.73 m2 for subjects 18-65 years and > 50 mL/min/1.73 m2 for subjects > 66 years
• Haemoglobin A1c (HbA1c) < 6.5% (< 48 mmol/mol)
• NT-proBNP (N-terminal prohormone of brain natriuretic peptide) < 125 ng/L or BNP (brain natriuretic peptide) < 35 ng/L

Exclusion Criteria:

• All known cardiovascular or cardiac diseases (evaluated using questionnaire; personal history of acute myocardial infarction (AMI) or other cardiac diseases (angina, stroke, atrial fibrillation, peripheral vascular disease (PVD), deep vein thrombosis (DVT), pulmonary embolism (PE), cardiac valve disease, heart failure)
• Treatment for hyperlipidaemia (medication reported in questionnaire)
• Hypertension (as judged by the investigator) or use of medication for hypertension (medication reported in questionnaire)
• Treatment for diabetes, including dietary treatment (reported in questionnaire)
• Abnormal BMI (body mass index) (< 18 kg/m2 or > 35 kg/m2), calculated from data collected during enrolment visit
• Current smokers (reported in questionnaire)
• Major illness or chronic disease that could affect the heart (lung, liver, unstable or nontreated thyroid disease, or autoimmune diseases (evaluated using questionnaire)
• History of cancer within the last 5 years (based on questionnaire) except basal cell carcinoma (in situ)
• Recent acute hospitalisation (within last 3 months, reported in questionnaire)
• Pregnancy (reported in questionnaire)
• Already included in the study

A minimum of 800 healthy subjects with a balanced gender distribution (minimum 400 females and 400 males).