An international team of researchers has developed a simple laboratory score that is safer and faster when diagnosing patients who visit the emergency department with symptoms of a heart attack. The score, published in CMAJ (Canadian Medical Association Journal), can also identify patients at risk for subsequent heart problems after discharge.
"We have developed a simple laboratory score that is superior to the use of cardiac troponin alone for the identification of patients at low and high risk of heart attack or death in the emergency department," said Dr. Peter Kavsak, McMaster University, Hamilton, Ontario. According to Professor Andrew Worster, also from McMaster University, "this lab score can reduce both the number of blood tests and the time spent in the emergency room for patients with chest pain."
Patients with symptoms of chest pain require multiple blood tests for several hours before a diagnosis is reached. Previous studies with highly sensitive cardiac troponin alone to rule out and rule in myocardial infarctions have not always shown sufficient safety for use in clinical practice.
In this international study, researchers from Canada, Australia, New Zealand and Germany combined common laboratory blood tests available in many hospitals around the world to create a single laboratory score or clinical chemistry score to diagnose a heart attack. These blood tests are part of the list of essential in vitro diagnostic tests for healthcare institutions with clinical laboratories of the World Health Organization.
The researchers validated the score for clinical chemistry as predictor of a heart attack or death within 30 days using data from 4245 patients from emergency room examinations in the four countries. Within one month of the visit of the emergency department, 727 heart attacks or the death of patients occurred. A negative (or low-risk) clinical chemistry score in the emergency department only missed one of these events compared to a maximum of 25 missed myocardial infarctions / death when using a highly sensitive cardiac troponin test alone. A positive (or high-risk) clinical chemistry score also identified approximately 75% of patients at high risk of heart attack or death when positive compared to a 40% low point was detected when the highly sensitive cardiac troponin test alone was positive. The score for clinical chemistry worked equally well for men and women.
The authors suggest that the score may be useful for standardizing diagnoses and improving safety.
"Applying the clinical chemistry correction algorithm would standardize the reporting of highly sensitive cardiac troponin test results, interpreting the tests within the normal range and representing an option that is less sensitive to both analytical and preanalytic errors, which could result in the safest laboratory approach for doctors to use when presenting at the emergency department, "Dr. Kavsak.
A more sensitive blood test diagnoses heart attacks faster
Peter A. Kavsak et al. Clinical chemistry score versus highly sensitive cardiac troponin I and T tests only to identify patients with a low or high risk of heart attack or death when presented to the emergency department, Canadian Medical Association Journal (2018). DOI: 10.1503 / cmaj.180144