Question asked by @Saroonahadnan via Twitter:
I have question about…what is the first cardiac marker in a heart attack? A troponin or CK-MB? Appreciate your help.
Answered by Dr. Guichard:
There are three generally accepted cardiac biomarkers that are analyzed as a panel – creatine kinase (CK), creatine kinase MB isoform (CK-MB), and cardiac troponin I or T (TnI or TnT). The absolute first marker to be elevated is the CK, however the CK is very nonspecific, meaning it can be elevated in many other health conditions other than a heart attack or myocardial infarction (MI). The most specific marker for heart damage is the TnI or TnT and, usually, the TnI or TnT only lags behind the CK by less than a couple hours. Most physicians rely on a patient’s history and presenting complaints along with the results of an electrocardiogram (ECG) and TnI or TnT assay before making any clinical decisions regarding an MI. Additionally, without getting too confusing, there are “high-sensitivity” TnI or TnT assays that are very sensitive and specific for heart damage. Researchers have shown that, in most cases, the high-sensitivity cardiac troponin assays are the first cardiac biomarkers to be elevated from damage to the heart. It should be noted and emphasized that heart damage can have many different causes; only one of those causes is an MI due to blockage(s) of the vessels around your heart. The physician in charge of your healthcare is best suited to make the final decisions regarding your diagnosis, treatment, and prognosis.