25 Jul 2018
Cardiac troponin is a marker of cardiac injury, enabling clinicians to aid in the diagnosis of myocardial infarction. Dr. Fred Apple, Director of Clinical Laboratories at Hennepin County Medical Center, describes how new IFCC recommendations and guidelines — for implementing high-sensitivity cardiac troponin assays — will improve cardiac triage and patient outcomes worldwide.
My name is Fred Apple. I am the Director of Clinical Laboratories here at Hennepin County Medical Center. I also serve as the Director of the Clinical Chemistry, Toxicology and Point of Care Testing Laboratories. In the academic side, I am a Professor of Laboratory Medicine at the University of Minnesota School of Medicine here in Minneapolis. Cardiac troponin is a protein that's found exclusively in the heart. So if you're going to...you've cut yourself, you bleed, with troponin, if you damage the heart in any way, cardiac troponin gets released from the muscle, it's found in the heart muscle, it gets into the circulation.
So, it's a marker of cardiac injury. In the appropriate clinical setting of ischemic heart disease, in combination with troponin, we can detect early on whether someone or not has had a heart attack. And that's the power of cardiac troponin. Detect myocardial injury, and in the appropriate clinical setting, rule in or rule out a heart attack.
Currently, cardiac troponin is the standard biomarker in clinical practice. Guidelines by the global taskforce, by the cardiology group, and the laboratory medicine, the IFCC Committee and the Academy of the AACC have put this marker almost on a pedestal. It is a standard marker. It's a very powerful tool.
All laboratories need to measure this marker. And where we're at now is clinicians rely on this marker to make good clinical decisions, such that if the protein is normal, you can rule out a heart attack. If the protein is evolving, normal at first but you follow serial changes which is the key here to look at over time, we make decisions on an evolving disease, in this case, it's a heart attack.
The goals and objectives of the IFCC Committee in collaboration with the AACC Academy are educational. They're educational and they're scientific. So our goal was to set rules, guidelines, and recommendations for all laboratories, not just in the US but internationally. The IFCC is an International Federation of Clinical Chemistry. Organizations, every country in the world has representation.
So, our small group of 8 or 9 members have drafted 10 recommendations to say how do we implement these? Proper quality control, proper regulatory testing, how to interpret results, how to report results, and all in combination of these 10 recommendations makes for a more universal, global use of these so they're commonly used appropriately.
These new IFCC guidelines really have a huge impact on patient care. First, we're going to develop sex-specific reference cut-offs. These cut-offs will be more powerful to discern changes in men and women because there are differences. Second, we're going to be able to measure with these high-sensitivity assays precise, accurate numbers.
There'll be no longer noise around the cut-off. Third, we're going to switch how we report things from a laboratory to the provider to the clinicians. They're used to seeing results at decimal points, .055. That's now going to become a 55. So, you won't get lost at even the scientific notation. What does this mean to the patient?
The results we report out will have within zero to three hours early rule out and early rule in. So instead of waiting six hours, we're going to have decisions in zero to three hours. What does it mean? Early discharge from the hospital will save millions and millions of dollars in the US, pounds in Britain, euros someplace else.
Early triage means they're going to get to the level of care they need to appropriately, and when you look at 30 day and 1 year outcomes, the outcomes will improve. So great impact in the laboratory for uniformity, great impact for patient care as far as getting the right treatment for the right patient. My future thoughts on troponin is everyone needs to switch to high-sensitive troponins.
Number two, everyone needs to use the 99th percentile upper reference limits so we have uniform cut-offs. Everyone needs to use sex-specific cut-offs. What that means for patient care? It's a precise assay, a very low value at presentation. You can get 30% to 50% of patients that are sent home. Huge cost savings in a healthcare system.
On the other side, early diagnosis within two hours, proper management, proper drug therapy will see huge improvement in healthcare outcomes. Those two things together in the patient care is going to save this world a lot of money.
Hennepin County Medical Center
Dr. Fred Apple is the medical director of the Clinical Laboratories, Clinical Chemistry, Clinical and Forensic Toxicology and Point of Care Testing at the Hennepin County Medical Center. He received his doctorate degree from the University of Minnesota in 1979 and obtained a fellowship in Laboratory Medicine in 1982 from Washington University. He is board certified in Clinical Chemistry and Toxicology. Dr. Apple serves as a principal investigator at the Minneapolis Medical Research Foundation. He is a consultant to the Hennepin County Medical Examiner’s Office. In addition to his investigative research, Dr. Apple is a Professor at the University of Minnesota Department of Laboratory Medicine and Pathology. Dr. Apple also serves as an Associate Editor for the journal Clinical Chemistry and is a Fellow of the American College of Sports Medicine.