An international team led by McMaster researchers has developed a simple laboratory score that is safer and faster at diagnosing patients who visit the emergency department with heart attack symptoms.

The score can also identify patients at risk of subsequent heart issues after discharge.

The details were published in the Canadian Medical Association Journal (CMAJ).

“We have developed a simple lab score that is superior to using cardiac troponin alone for the identification of patients at low and high risk for heart attack or death at emergency department presentation,” said Peter Kavsak, co-study lead and a professor of pathology and molecular medicine at McMaster’s Michael G. DeGroote School of Medicine.

Patients with chest pain symptoms require multiple blood tests over several hours before a diagnosis is reached. Previous studies using high-sensitivity cardiac troponin alone to rule out and rule in heart attacks have not consistently demonstrated sufficient safety to use in clinical practice.

“This lab score may reduce both the number of blood tests and time spent in the emergency department for chest pain patients,” said Andrew Worster, co-study lead and professor of medicine at the Michael G. DeGroote School of Medicine.

In this international study, researchers from Canada, Australia, New Zealand and Germany combined common laboratory blood tests available at many hospitals around the world to create a single laboratory score, or clinical chemistry score, to diagnose heart attack. These blood tests are part of the World Health Organization’s list of essential in-vitro diagnostics tests for health care facilities with clinical laboratories.

The researchers validated the clinical chemistry score as a predictor of heart attack or death within 30 days, using data on 4,245 patients from emergency department studies in the four countries. Within one month of the emergency department visits, 727 heart attacks or deaths in patients occurred.

A negative (or low-risk) clinical chemistry score at emergency department presentation missed only one of these events, compared with up to 25 missed heart attacks/death when using a high-sensitivity cardiac troponin test alone. A positive (or high-risk) clinical chemistry score also identified about 75 per cent of patients at high risk of heart attack or death when positive compared with a low of 40 per cent detected when the high-sensitivity cardiac troponin test alone was positive. The clinical chemistry score worked equally well in men and women.

The authors suggest the score can be useful for standardizing diagnoses and improving safety.

“Adoption of the clinical chemistry score algorithm would standardize reporting of high-sensitivity cardiac troponin test results, how the tests are interpreted in the normal range, and represent an option less susceptible to both analytical and preanalytical errors,” said Kavsak.

“This could result in the safest laboratory approach for physicians to use at presentation in the emergency department.”

The Canadian Institutes of Health Research funded the study with reagent support from Abbott Laboratories and Roche Diagnostics.

Read the paper here.