TSIX diagnostic study: Establishing a new global standard in ACS care

• The TSIX study program is a pioneering effort to establish a new global standard for a high-sensitivity troponin assay
• Its rigorous design, diverse population, and real-world settings ensure the clinical data is globally applicable and highly reliable
• The results of this diagnostic study provide a robust scientific foundation for confident, efficient, and standardized patient triage in the emergency department, enhancing ACS care

Chest pain is a top reason for emergency care visits, causing patient anxiety whilst putting pressure on healthcare services.^1,2 Only one in ten patients with symptoms is actually having a heart attack.² With frequent overcrowding in emergency departments globally,³ quickly and reliably identifying or ruling out acute myocardial infarction (AMI) is crucial for patient outcomes.

While high-sensitivity troponin assays are the gold standard for diagnosis,⁴ challenges persist, including inconsistent interpretation of low-level values⁵ and the need for more globally validated data. Addressing these challenges requires a solid scientific foundation.

The TSIX study program is a comprehensive global diagnostic study and the largest of its kind for a high-sensitivity troponin assay, setting a new standard in ACS care.^1,6 The program's robust approach and rigorous methodology make its findings highly relevant for clinical practice worldwide.

The significance of the TSIX study program lies in its unique and robust design. With over 13,000 participants from diverse populations across the US, China, Japan, and the EU, the study's design ensures its real-world applicability.⁶ The program is composed of two key studies: REF-TSIX and PERFORM-TSIX.

• The REF-TSIX study was a landmark effort to establish the standard upper reference limits (URLs) for troponin levels in a healthy population.⁶ It is the first study to apply stringent International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) exclusion criteria to define a truly healthy population, preventing inflated thresholds that could delay diagnosis.^6,7 This approach resulted in the establishment of overall and sex-specific 99th percentile URLs:
  • Overall population 99th percentile URL: 27 ng/L
  • Female-specific 99th percentile URL: 18 ng/L
  • Male-specific 99th percentile URL: 32 ng/L
• The PERFORM-TSIX study validated the clinical performance of new URLs and the assay's performance within the European Society of Cardiology (ESC) recommended rapid diagnostic algorithms in a real-world setting. Enrolling over 5,600 patients across 50 clinical centers worldwide, the study demonstrated the assay's high effectiveness in identifying heart attacks and high safety in ruling them out. Notably, 56.6% of patients were discharged within the first hours with a negative predictive value of 99.7%, underlining its excellent clinical performance.^8,9

The rigorous methodology of the TSIX study ensures that the assay provides high analytical sensitivity and is globally applicable. The program's design validates three core pillars of the high-sensitivity Troponin T assay: precision, robustness, and global validation.^10,11

• Precision: The study results showed that the assay can aid in the diagnosis of myocardial infarction.
• Robustness: The assay was confirmed to be resistant to interferences, meaning it provides reliable results regardless of sample quality.
• Global validation: Most importantly, the TSIX study proved consistent performance across different regions, supporting the use of a single global cutoff value for standardized ACS care around the world.

The comprehensive data from the TSIX study program gives clinicians the confidence to interpret even the smallest changes in high-sensitivity Troponin T levels. This is a significant advancement in managing acute myocardial infarction (AMI) and ensuring patients receive the right treatment at the right time.

The TSIX study provides robust evidence for future innovations, such as new ACS biomarkers, devices, and algorithms, aiming to improve outcomes and efficiency in the emergency department.

Roche stays at the forefront of extensive clinical validation, and we will continue to fund the most impactful studies and generate evidence that seeks to enhance ACS care further.