A surreal illustration symbolizing rapid heart attack diagnosis.

Fast Track Heart Attack Diagnosis: Is the FDA's Approach Safe?

Mira Elwood in Health & Wellness July 2025 • 4 min read.

"A new study examines the effectiveness of a rapid diagnostic algorithm for myocardial infarction (MI) using the FDA-approved high-sensitivity troponin T assay."

Diagnosing a myocardial infarction (MI) quickly is critical for saving lives. Recently, the FDA approved a new high-sensitivity cardiac troponin T (hs-cTnT) assay, offering a potentially faster way to detect heart attacks. For years, countries in Europe, Australia, and Canada have been using more sensitive tests which helped them quickly identify MI cases at an early stage.

These countries developed what's called the 0/1-h algorithm. This strategy involves measuring troponin levels at the patient's arrival to the emergency department (ED) and again after just one hour. Based on these levels, doctors can quickly decide whether to rule out or rule in MI.

However, the FDA's approved version of the hs-cTnT assay has a couple of key differences compared to how it's used elsewhere. First, it reports very low concentrations differently. Second, the FDA-approved 99th percentile upper reference limit (19 ng/l) is a bit higher. Given these differences, a new study was needed to see how well the 0/1-h algorithm performs in the FDA-approved setting.

Does the FDA-Approved Approach Compromise Accuracy?

A surreal illustration symbolizing rapid heart attack diagnosis.

Researchers conducted a large, multi-center study to evaluate the 0/1-h algorithm using the FDA-approved hs-cTnT assay. The study involved patients presenting to the ED with suspected MI, excluding those with ST-segment elevation MI. Two independent cardiologists reviewed each case to make a final diagnosis, considering all available clinical information.

The 0/1-h algorithm was applied in two ways: using the original algorithm (reporting hs-cTnT concentrations down to 3 ng/l, direct rule-out at <5 ng/l, and a 99th percentile of 14 ng/l), and using a modified algorithm based on FDA approval (direct rule-out at <6 ng/l and a 99th percentile of 19 ng/l). The study also assessed the 0/3-h algorithm.

Safety First: The negative predictive value (NPV) and sensitivity for MI were extremely high and similar for both the original and modified 0/1-h algorithms (NPV around 99.8-99.9%, sensitivity around 99.4-99.6%).
Quick Rule-Out: The 0/1-h algorithms effectively ruled out and ruled in MI in approximately 75% of patients.
Comparable Performance: The rule-in performance was also excellent and comparable between both 0/1-h algorithms.

The results showed that both the original and the FDA-modified 0/1-h algorithms performed very well, with high safety and comparable efficacy. This suggests that using hs-cTnT as approved by the FDA can provide a safe and effective way to triage patients and rapidly rule out or rule in MI.

The Bottom Line: Rapid, Safe Heart Attack Assessment

The study indicates that the 0/1-h algorithm, when used with the hs-cTnT assay approved by the FDA, offers a safe and effective approach to quickly assess patients with suspected MI. The differences in the FDA-approved assay's reporting and 99th percentile value do not appear to compromise the algorithm's accuracy or safety.

For patients, this means potentially faster diagnosis and treatment decisions. For healthcare providers, it provides reassurance that the 0/1-h algorithm can be reliably implemented in the U.S. setting.

Further research may explore ways to optimize the algorithm and improve its performance even further. But for now, the 0/1-h algorithm with the FDA-approved hs-cTnT assay represents a valuable tool for improving the speed and accuracy of heart attack diagnosis.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.jacc.2017.07.746, Alternate LINK

Title: Effect Of The Fda Regulatory Approach On The 0/1-H Algorithm For Rapid Diagnosis Of Mi

Subject: Cardiology and Cardiovascular Medicine

Journal: Journal of the American College of Cardiology

Publisher: Elsevier BV

Authors: Raphael Twerenbold, Patrick Badertscher, Jasper Boeddinghaus, Thomas Nestelberger, Karin Wildi, Maria Rubini Gimenez, Òscar Miró, F. Javier Martín-Sánchez, Tobias Reichlin, Christian Mueller

Published: 2017-09-01

Related Articles

Everything You Need To Know

1

What is the 0/1-h algorithm?

The 0/1-h algorithm is a diagnostic strategy used to quickly assess patients for Myocardial Infarction (MI), or heart attack. It involves measuring high-sensitivity cardiac troponin T (hs-cTnT) levels in a patient's blood upon arrival at the emergency department (ED) and again one hour later. This allows doctors to rapidly determine whether to rule out or rule in an MI, which is critical for timely treatment.

2

What is high-sensitivity cardiac troponin T (hs-cTnT), and why is it important?

High-sensitivity cardiac troponin T (hs-cTnT) is a biomarker, a substance whose presence indicates a specific condition in this case, Myocardial Infarction (MI). It is measured using the hs-cTnT assay. The hs-cTnT assay detects even small increases in troponin levels. Elevated troponin levels, especially when increasing over time, suggest heart muscle damage, a hallmark of MI. The FDA-approved version of the hs-cTnT assay is crucial because it directly impacts how the 0/1-h algorithm is used in the United States. The study investigated its safety and efficacy, which is very important for clinical care.

3

Why is the 0/1-h algorithm important for diagnosing heart attacks?

The 0/1-h algorithm is significant because it enables faster diagnosis of Myocardial Infarction (MI). This rapid assessment is critical because prompt treatment significantly improves patient outcomes. The algorithm's ability to quickly rule out MI reduces unnecessary hospital stays and tests, while its ability to rule in MI allows for immediate intervention. The speed and accuracy provided by this method can lead to saving lives. The use of the FDA-approved hs-cTnT assay within this algorithm ensures that the process can be standardized, potentially leading to widespread adoption of this method, improving patient outcomes in many regions.

4

How does the FDA-approved version of the hs-cTnT assay differ from other versions, and why does it matter?

The main difference between the original 0/1-h algorithm and the FDA-approved version lies in how the high-sensitivity cardiac troponin T (hs-cTnT) assay is used. The FDA-approved version reports lower concentrations differently, which can impact the algorithm's interpretation. Additionally, the FDA-approved 99th percentile upper reference limit (19 ng/l) is a bit higher than that used in the original algorithm. The study evaluated these differences to ensure the modified approach maintains its safety and accuracy, which is very important when used in a clinical setting.

5

What are the key takeaways from the study regarding the 0/1-h algorithm and FDA-approved hs-cTnT assay?

The study's findings indicate that the FDA-modified 0/1-h algorithm, using the FDA-approved high-sensitivity cardiac troponin T (hs-cTnT) assay, is safe and effective for rapidly assessing patients with suspected Myocardial Infarction (MI). It effectively rules out and rules in MI in a large percentage of patients, with high negative predictive value (NPV) and sensitivity. This means that clinicians can confidently use this method to make quick decisions about patient care, leading to faster diagnosis, quicker treatment, and improved patient outcomes in cases of heart attack.