Understanding troponin part 2

Podcast – Understanding Troponin Part 2

Welcome to the St Emlyn’s podcast. In this episode, we’re diving deep into the world of high-sensitivity troponins (hs-Tn) and exploring their significance in emergency medicine. This post is based on insights shared by Iain Beardsell and Rick Body in their podcast series. If you’re an emergency physician keen on optimizing your use of hs-Tn assays, this one’s for you!

Listening Time – 26:31

Understanding High Sensitivity Troponins

Introduction to High-Sensitivity Troponins

High-sensitivity troponins (hs-Tn) are revolutionizing how we detect and manage myocardial infarctions (MI) in emergency departments (ED). Unlike traditional assays, hs-Tn tests can detect much lower concentrations of troponin, a protein released during myocardial injury. This enhanced sensitivity allows for earlier and more accurate detection of cardiac events.

Analytical Sensitivity vs. Diagnostic Sensitivity

Understanding the difference between analytical and diagnostic sensitivity is crucial. Analytical sensitivity refers to the assay’s ability to detect low concentrations of troponin, whereas diagnostic sensitivity relates to the test’s performance in diagnosing acute myocardial infarctions (AMI).

Key Points on Analytical Sensitivity:

  • Detection Threshold: High sensitivity troponin assays can detect troponin in over 50% of healthy individuals.
  • Precision: These assays have a coefficient of variation (CV) of less than 10% at the diagnostic threshold, ensuring consistent results.

Diagnostic Sensitivity:

  • Improved Detection: Studies show that hs-Tn assays have a higher diagnostic sensitivity (90-92%) than older assays (80-85%).
  • Early Rule-Outs: This makes hs-Tn particularly valuable for ruling out AMI in patients presenting with chest pain in the ED.

High Sensitivity Troponin Assays: A Closer Look

To illustrate, let’s focus on the Roche troponin T high- sensitivity assay:

  • 99th Percentile Cutoff: 14 nanograms per liter.
  • Detection Range: Can detect levels as low as 3 nanograms per litre.
  • Higher Readings: It’s common for hs-Tn assays to give higher readings than older assays for the same sample, which affects the diagnostic threshold.

The Balance Between Sensitivity and Specificity

While hs-Tn assays improve sensitivity, they may reduce specificity:

  • More Positives: Lowering the diagnostic threshold results in more positive results, increasing diagnostic sensitivity but reducing specificity.
  • Predictive Value: For example, a positive hs-Tn T result at patient arrival has a specificity of around 70% and a positive predictive value of 50%.

Using High-Sensitivity Troponins in the Emergency Department

Early Rule-Out Protocols

The most significant advantage of hs-Tn assays is their potential to expedite the rule-out process:

  • Zero and Three-Hour Protocols: Studies suggest that hs-Tn assays can effectively rule out AMI with samples taken 0 and 3 hours after arrival instead of the traditional 6-hour wait.
  • Efficiency: This protocol can significantly speed up patient throughput in the ED, reducing congestion and wait times.

Understanding Deltas

Delta refers to the change in troponin levels between tests:

  • Absolute vs. Relative Deltas: Absolute changes (e.g., an increase of 10 nanograms per liter) are often more reliable than relative percentage changes.
  • Clinical Context: It’s crucial to interpret deltas in the context of the patient’s overall clinical picture.

Practical Considerations for Emergency Physicians

Incidental Troponin Elevations

With increased testing at the front door, incidental findings are inevitable:

  • Low Pre-Test Probability: A positive hs-Tn result often does not indicate AMI in patients with a low pre-test probability of AMI (e.g., mechanical falls).
  • Clinical Judgment: Before making a decision, consider repeating the test and evaluating the patient’s history and clinical presentation.

Patients with Comorbidities

Troponin levels can be elevated in patients with various comorbidities:

  • Age and Chronic Conditions: Older patients and those with conditions like LV dysfunction may have higher baseline troponin levels.
  • Reference Ranges: Use broader reference ranges for patients with comorbidities, as suggested by studies from Paul Collins and colleagues.

Future Directions and Guidelines

Ongoing Research

Research and guidelines on hs-Tn usage are continually evolving:

  • NICE Guidelines: Recommendations on using hs-Tn in clinical practice are expected to be published, providing clearer protocols for emergency physicians.
  • Early Adoption: As new evidence emerges, early adopters must balance innovation with patient safety.

Point-of-Care Testing

While hs-Tn assays currently require large analyzers, point-of-care testing remains a goal:

  • Future Developments: Advances in technology may eventually make hs-Tn testing available at the bedside, further streamlining ED workflows.


High-sensitivity troponins represent a significant advancement in the early detection and management of myocardial infarctions in the emergency department. By understanding the nuances of analytical and diagnostic sensitivity, utilizing early rule-out protocols, and interpreting results within the clinical context, emergency physicians can leverage these assays to improve patient care. As always, ongoing research and adherence to evolving guidelines will be essential in optimizing the use of hs-Tn in clinical practice.

For more insights and updates, stay tuned to the St Emlyn’s blog and feel free to reach out with your questions and experiences. Together, we can continue to advance emergency medicine for the benefit of our patients.

Podcast Transcription

Where to listen

You can listen to our podcast in numerous ways, ensuring you never miss an episode no matter where you are or what device you’re using. For the traditionalists, Apple Podcasts and Google Podcasts offer easy access with seamless integration across all your Apple or Android devices. Spotify and Amazon Music are perfect for those who like to mix their tunes with their talks, providing a rich listening experience. If you prefer a more curated approach, platforms like Podchaser and TuneIn specialize in personalising content to your tastes. For those on the go, Overcast and Pocket Casts offer mobile-friendly features that enhance audio quality and manage playlists effortlessly. Lastly, don’t overlook YouTube for those who appreciate a visual element with their audio content. Choose any of these platforms and enjoy our podcast in a way that suits you best!

Cite this article as: Iain Beardsell, "Podcast – Understanding Troponin Part 2," in St.Emlyn's, August 7, 2014, https://www.stemlynsblog.org/podcast-troponin-2/.

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