Imagine that a simple puff of air from your lungs could tell doctors whether you have asthma, or tuberculosis, or lung cancer -- or other serious health problems. That reality is closer than you think. Breath tests for these life-threatening illnesses and more are available today, or will be soon, thanks to fast-moving research into high-tech sensors and how diseases affect the chemistry of breath. Here are five of the most intriguing tests:
1. Breath test for asthma
An asthma attack can come on suddenly, closing off airways and sending you to the emergency room, or worse, which is why those with asthma have to keep close tabs on inflammation in their lungs and bronchial tubes. Just in the past few years, though, cutting-edge breath-testing machines have arrived in hospitals and clinics. These devices can tell doctors whether you have asthma -- or whether, as an asthma patient, your meds are working -- with a simple exhale. And on the horizon: a pocket-size handheld breath tester, announced by Siemens, that will allow people with asthma and allergies to measure their risk of asthma attack on the go.
What the test does: Measures nitric oxide in breath. "Nitric oxide is produced by inflammatory cells in the airways called eosinophils," says allergist David Bernstein, M.D., of the University of Cincinnati College of Medicine. "When nitric oxide levels rise above 40 or 50 parts per billion, it's a specific reflection of inflammation in the lungs; there's really nothing else that could cause this."
Why it's important: Prior to the introduction of breath tests several years ago, people with asthma or at risk for asthma had to rely mostly on a sputum test, which requires lab analysis -- a process that can take days. That's not much help when you can't breathe and don't know why, or you already know you have asthma but not whether an asthma attack might be imminent. Breath tests provide results on the spot and offer a potentially life-saving warning that an asthma attack is imminent. "These tests give you a biomarker for what's going on in the lungs," Bernstein says, "so it's almost a way to peek directly into the lungs."
What else you can do: The gold standard of care for people with asthma who can't get to a clinic or hospital today is to monitor lung function with a peak-flow meter, to control symptoms with long-term medication, and to have an action plan in place for asthma attacks, which usually includes taking higher doses of inhaled and oral steroids.
2. Breath test for tuberculosis
Tuberculosis, a bacterial infection in the lungs, is a threat once again, thanks to increased travel and immigration, the increase in of antibiotic-resistant strains, and higher numbers of people with immune systems compromised by other conditions. It can also be deadly if undetected and untreated.
Soon, though, hospitals and public health clinics will be able to tell you in minutes whether you have TB simply by having you breathe into a small tube. BreathLink, a desktop system that feeds into a computer, was developed by Menssana Research, a New Jersey biotech company founded by Michael Phillips as an offshoot of his research at New York Medical College. The U.S. Air Force and the National Institutes of Health are funding studies in hopes of making it widely available.
What the test does: Measures and concentrates the levels of specific volatile organic compounds (VOCs) in the breath, then sends the data to a computer, which analyzes the results in under 7 minutes.
Why it's important: TB scares public health professionals because it's easily spread and because many people carry the disease without having symptoms. In fact, only 5-10 percent of those infected with TB will develop the disease. We've all had the skin-prick test for tuberculosis -- and have waited several days for a reaction before going back in for a follow-up visit to determine that we're TB-free. Because tuberculosis is easily spread, teachers, daycare employees, health workers, students, and even parents who volunteer in the classroom need to be TB-free, so TB tests are required for pretty much any profession that puts you in close contact with people.
What else you can do: You can still visit your local public health clinic for a TB skin test. And it's important to be on the watch for TB symptoms, which include fever, persistent cough, weight loss, and lack of energy.
3. Breath test for lung cancer
The main reason lung cancer is so deadly, killing more than 80 percent of those diagnosed within five years, is that it's caught too late; the lungs are simply too difficult for doctors to "see" into. That could change with a new breath test for lung cancer, currently completing late-phase clinical trials and headed for market within two years.
What the test does: Detects a distinctive pattern of 22 chemicals, most of them alkanes and methylalkanes, in the breath of those with lung cancer. "Our research shows the sensitivity and specificity of this test is as good as any serum or plasma biomarker test, and it's quicker and less invasive," says Harvey Pass, director of thoracic surgery and thoracic oncology at New York University's Langone Cancer Center, who's overseeing clinical trials of Menssana's technology. Because there are different patterns for different malignancies, Menssana is also evaluating its breath tests for efficacy in diagnosing breast cancer, and the results look extremely promising, Pass says.
Why it's important: More people in the United States die from lung cancer each year than from any other type of cancer, according to the Centers for Disease Control and Prevention. Recent data show that lung cancer deaths can be cut by 20 percent with CT scans, but, because of the high costs of screening, it's impossible to screen the entire population with scans. "With this quick, relatively cheap test, we could sort out people whose breath reveals the profile of lung cancer and offer them CT scans," Pass says.
What else you can do: If you're at high risk for lung cancer, either because you're a smoker or a former smoker or you have a family history of lung cancer, enroll in one of Menssana's clinical trials for lung cancer breath testing around the country. Ohio residents may be interested in ongoing research at the Cleveland Clinic, where physician Peter Mazzone is working with a company called ChemSensor to develop a different lung cancer breath test that analyzes the chemical output of the breath with color-changing sensors. Mazzone says the tests have had 85 percent accuracy in singling out people with lung cancer, though they're still in an early stage of development.
And in the coming years, clinics may use cancer-sniffing dogs to detect various types of tumors. The Pine Street Clinic, in San Anselmo, California, has been working with cancer-sniffing dogs for years, and recent small studies in Japan and France showed that specially trained dogs can detect colon and prostate cancer by sniffing urine and stool samples.
4. Breath test for H. pylori infection
Linked to Peptic ulcers and stomach cancer, a bacterial infection of the stomach and upper intestine, is the Helicobacter pylori (H. pylori) bacteria. Early and accurate testing and identification for H. pylori is life saving, which is why gastroenterologists are so excited about a new breath test available at many hospitals and clinics.
What the test does: Analyzes the breath before and after the subject drinks a lemon-flavored solution of urea to detect ammonia and carbon dioxide, which are released as by-products of the bacteria's digestion. The test can identify nearly all people who have H. pylori infection.
Why it's important: H. pylori can cause a range of symptoms that can be hard to pinpoint and find a cause for, so it often goes undetected. And left untreated, an H. pylori infection can lead to peptic ulcers and even eventually to stomach cancer.
What else you can do: Not all hospitals have breath-testing apparatus available, since it's quite new. H. pylori can be detected with a blood antibody test or a stool antigen test. If you have ulcers or serious symptoms and doctors don't know the cause, an endoscopy and biopsy can be used to take a sample from the stomach and the intestinal lining.
5. Breath test for heart-transplant rejection
What if, having received a new heart, you could find out with a simple breath if your body was accepting the transplanted organ? That's the temptation offered by HeartsBreath, the first product of Menssana Research to reach the market.
What it does: Detects alkanes, a type of VOC released as a result of oxidative stress, in the breath of posttransplant heart patients.
Why it's important: Studies show that a negative breath test with Heartsbreath is as accurate in detecting transplant rejection as a ventricular biopsy, says Menssana CEO Michael Phillips. And wouldn't you rather have a breath test than a biopsy?
What else you can do: The main problem with HeartsBreath is that because it's so new, many insurers aren't covering it yet. You can appeal your insurance company's decision, which is usually based on designating it an "experimental" procedure; many patients are doing so successfully. Otherwise, the tests available are a gene-expression test called AlloMap, also considered experimental by some insurers, or endomyocardial biopsy, the traditional standard of care.