A heart attack is a life-changing medical emergency. The sooner a heart attack is diagnosed and treated, the sooner blood flow can be restored to the organ, which means less damage will occur. When damage does happen, one of the markers used to detect it is called troponin.
The initial findings of the research were presented at the European Society of Cardiology (ESC) Congress last week. One of the researchers, Roi Westreich, MD, PhD, of the Soroka University Medical Centre in Beer Sheva, Israel, demonstrated that troponin can be detected in a saliva sample more rapidly than it can be in a blood sample.
Westreich tells Verywell he and his colleagues tested the saliva of 41 patients with elevated blood troponin levels and compared the results to the troponin levels of 66 healthy volunteers. The samples were tested before and after being treated with a process called Saliva High Abundant Proteins Effective Depletion (SHAPED) that removes excess proteins from the saliva.
“Since no test has been developed for use on saliva, we had to use commercially available tests intended for whole blood, plasma, or serum, and adjust them for saliva examination,” Yoav Neumann, PhD, the study’s lead scientist on behalf of Salignostics, Ltd., said in a press release that was published by the ESC.
The researchers found that 84% of the processed saliva samples from participants with troponin in their blood also showed evidence of troponin. Only 6% of the unprocessed saliva samples showed troponin.
Patients with lower blood troponin levels were less likely to have positive saliva results. The samples from healthy volunteers yielded a 10% false-positive rate.
How Could This Help Patients in the Future?
The researchers’ ultimate goal is to develop a test that could be performed before a patient gets to the hospital. “It will be calibrated to show positive results when saliva troponin levels are higher than a certain threshold and show a yes/no result, like a pregnancy test,” Westreich says.
The test requires no electrical power, which makes it portable and convenient to use outside of the hospital. A saliva test is also much quicker than a blood test: saliva troponin levels can be measured in 10 minutes, whereas a traditional blood test in the lab can take 30 to 60 minutes.
The time saved is significant because the sooner a heart attack is diagnosed and treated, the less permanent damage will occur in the heart.
“If we could detect heart attacks sooner, it would mean lower morbidity, less heart failure, and fewer scars [in the heart muscle] causing cardiac arrhythmias,” Jennifer Haythe, MD, a board-certified cardiologist with ColumbiaDoctors at NewYork-Presbyterian Hospital, tells Verywell. Haythe was not involved with the saliva research.
Challenges of a Saliva Test
Physicians do not always wait for a patient’s troponin results to treat a heart attack, Haythe says. If there are certain abnormalities in a patient’s EKG rhythm, immediate action is required.
“If someone comes in with a classic presentation of a STEMI, you would not wait for blood work to come back, because the diagnosis is apparent anyway,” Haythe says.
A non-ST segment elevation myocardial infarction (NSTEMI) is usually a partial or temporary blockage. While it is a less severe type of heart attack, it still requires urgent medical attention.
Another disadvantage to saliva troponin tests is that they only produce negative or positive results, while blood tests can show the exact troponin level.
“Troponin levels risk-stratify patients,” Haythe says, adding that higher troponin levels mean a greater risk of complications.
Additionally, troponin is not always an indicator of a heart attack.
“You can have chest pain for days and not necessarily have a positive troponin,” Haythe says, but “people can also have low troponin levels in renal failure and chronic heart failure.”
An initial false-positive on a troponin test is not necessarily significant because a patient will have their troponin levels checked every six hours at the hospital.
While the first results of the research are promising, Westreich says that there are still a lot of unknowns. “Further research is needed to determine how long troponin stays in the saliva after a heart attack,” he says. “In addition, we need to know how many patients would erroneously be diagnosed with a heart attack and how many cases would be missed.”
“It really will come down to whether they can show that people who are having cardiac injury are having troponin measured in the saliva in a reliable way,” Haythe says. “This test really needs to be validated and studied extensively before anybody will use it.”
