A blood test could detect early development of emphysema before symptoms become apparent, according to a new study.
The test detects early emphysema 95 percent of the time and has the potential to persuade a person to stop smoking before his or her emphysema worsens, said study researcher Dr. Ronald G. Crystal, professor of genetic medicine at Weill Cornell Medical College and chief of pulmonary and critical care medicine at New York-Presbyterian Hospital/Weill Cornell Medical Center.
"People will stop smoking if they have lung disease, but if they can't see any symptoms, they won't think anything's wrong," Crystal told MyHealthNewsDaily. "But this is the first test that tells you early, before you develop abnormalities that cause you to be short of breath, that there's damage ongoing in your lung that can lead to emphysema."
The test measures blood levels of endothelial microparticles (EMPs), which are shed when the blood vessels surrounding the lung's air sacs are damaged, usually from smoking.
The air sacs are where oxygen-carbon dioxide exchanges occur: Blood vessels bring carbon dioxide from around the body to release into the air sacs, and oxygen in the sacs is taken by the blood to be transported around the body.
That's why people experience shortness of breath when they have emphysema they can't take in enough oxygen to breathe and can't remove enough carbon dioxide from their blood, the study said.
But this test would be able to tell a smoker that he or she is developing emphysema before these problems set in.
"It's like a smoke alarm: If you have one in your apartment and it goes off, it doesn't mean you have a fire, but it says you better watch out," Crystal said.
Emphysema and chronic bronchitis make up chronic obstructive pulmonary disease, a type of chronic lower respiratory disease that is the fourth-leading cause of death in the United States, according to the Centers for Disease Control and Prevention.
Crystal and his colleagues conducted the EMP blood test on 92 people who were healthy nonsmokers, healthy smokers or smokers with evidence of lung destruction.
Patients also underwent spirometry, which measures the volume and speed of air as it's inhaled and exhaled, and DLCO, an emphysema-detection test that must be administered by a pulmonologist.
Researchers found that the EMP test had a 95 percent success rate in telling which patients had early emphysema, which was verified by the DLCO test, the study said.
The researchers replicated the study in two more groups of similar patients, which also yielded a 95 percent success rate in finding signs of emphysema.
The DLCO test is currently used to confirm suspicions of emphysema, but a potential EMP test would be a low-cost, easy way for doctors to screen for the disease even when there are no symptoms, Crystal said.
When doctors draw blood during patients' annual physicals, the blood sample could be sent to the lab to be tested for EMP along with all the other typical blood tests, he said.
But Crystal said more clinical trials are needed before the blood test can be used regularly in doctor's offices.
The study will be published online March 14 in the American Journal of Respiratory and Critical Care Medicine.
Pass it on: A future blood test could tell a smoker whether he or she has emphysema even before symptoms set in.
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Follow MyHealthNewsDaily staff writer Amanda Chan on Twitter @AmandaLChan.
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