There are many little health checks people can do at home ― from checking your pulse to breast self-exams. But one that might be less familiar is the thumb test.
It’s a relatively simple maneuver, but it has the potential to reveal clues about a possible heart issue.
So what exactly does the “thumb test” entail and what should people know about it? Below, cardiologists break it down.
What is the thumb test?
“The thumb test is an easy test people can do to see if they are at increased risk for an aortic aneurysm,” preventative cardiologist Dr. Tracy Paeschke told HuffPost. “The thumb test involves laying your thumb across your flat palm. If your thumb extends beyond the edge of your palm, this indicates joint laxity or stretchiness, which can be associated with connective tissue diseases.”
Connective tissue diseases such as Marfan syndrome and Ehlers-Danlos syndrome are associated with a higher risk of aneurysms, particularly aortic aneurysms, because people with these conditions tend to have weakened blood vessel walls.
Also known as the thumb-palm test, the thumb test doesn’t necessarily indicate that someone currently has an aneurysm. Rather, it helps detect the kind of joint hypermobility linked to these disorders ― which carry an increased risk of aneurysms.
“A study in 2021 showed that people with a positive thumb sign had a high likelihood of having an ascending aortic aneurysm, widening of the large blood vessel in the chest that carries blood from the heart to all parts of the body,” Paeschke said.
What are the limitations of the thumb test?
“Remember this is not a diagnostic test,” said Dr. Marc Bonaca, a cardiologist and vascular medicine specialist and chair of the American Heart Association PAD Collaborative. “Most people with an aortic aneurysm will have a negative thumb test. Those who have a positive thumb test may have a connective tissue condition associated with aneurysm, but that does not mean they have an aneurysm.”
Indeed, that same 2021 study that found those with a positive test were more likely to have an aortic aneurysm also noted that “the majority of aneurysm patients do not manifest a positive thumb-palm sign.” Thus, a negative result does not exclude having an aneurysm.
“The thumb test is not considered accurate or reliable as a screening tool for an aortic aneurysm,” said Dr. Tarak Rambhatla, a cardiologist with Miami Cardiac & Vascular Institute of Baptist Health South Florida. “Many healthy people may have a ‘positive’ test without any mixed connective tissue disease or any vascular disease. And conversely, many others with aneurysms may have a normal thumb test. Screening for aneurysm is done with imaging such as echocardiography, CT or ultrasound ― not physical maneuvers.”
He believes the thumb test is “an interesting bedside sign linked to connective tissue disorders” but otherwise can be misleading.
“A positive result is nonspecific and may cause unnecessary anxiety, while a negative result may provide false reassurance to someone who actually has an aneurysm,” Rambhatla said. “Over-reliance on it could delay proper screening or surveillance with imaging in high-risk individuals. In short, it should never replace formal medical evaluation or guideline-based aneurysm screening.”
Dr. Glenn Hirsch, a cardiologist and chief of the division of cardiology at National Jewish Health, also emphasized that other factors are more predictive of the presence of an aortic aneurysm than the thumb test ― like cardiovascular issues or a family history of aneurysms.
“There are other causes of aortic aneurysms in the chest such as high blood pressure, and this test would be less helpful in that situation,” Hirsch said.
What should you do if you have a positive thumb test?
“If you have a positive thumb test you should talk to your doctor about whether this could suggest an underlying connective tissue disease and whether you should have additional testing,” Bonaca said, adding that your doctor might do a more complete physical exam and order certain scans. “Aneurysms are diagnosed with imaging, and guidelines recommend testing for specific reasons in people at risk.”
He noted that imaging is the gold standard for diagnosing aneurysms, and there are medical guidelines that recommend testing based on assessment of certain risk factors.
“If someone with a positive thumb test also has features suggestive of Marfan syndrome, Ehlers-Danlos or a family history of aneurysm or dissection, they should discuss it with a physician who may recommend formal evaluation and imaging of the aorta,” Rambhatla said. “If it’s an isolated finding in an otherwise healthy person, it usually does not warrant urgent concern but can be brought up at a routine medical visit for context.”
Hirsch also recommended that people discuss risk factors with their physicians to determine when screening and monitoring is appropriate.
“Some of the risk factors for aortic aneurysms include age over 65, men, smokers, high blood pressure, connective tissue disorders or a family history of aortic aneurysms and the presence of bicuspid aortic valves,” he said.
He also pointed to other potential signs of an underlying connective tissue disorder beyond the thumb test ― such as being “double-jointed,” having joint dislocations and even losing teeth.
“Ultimately, awareness of the thumb test can prompt useful conversations,” Rambhatla said. “But medical decision-making should always be guided by evidence-based screening and imaging.”
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