COPD Diagnosis Understanding the Differential Diagnosis of COPD Why the exclusion of other causes is needed By Deborah Leader, RN Deborah Leader RN, PHN, is a registered nurse and medical writer who focuses on COPD. Learn about our editorial process Deborah Leader, RN Medically reviewed by Medically reviewed by Sanja Jelic, MD on September 18, 2020 Sanja Jelic, MD, is board-certified in sleep medicine, critical care medicine, pulmonary disease, and internal medicine. Learn about our Medical Review Board Sanja Jelic, MD on September 18, 2020 Print There are many medical conditions that can be easily diagnosed with a blood test or physical exam. Others are not so simple. In some cases, there will be no single test or procedure that can either confirm or exclude the presence of an illness. Congestive obstructive pulmonary disease (COPD) is a case in point. While various respiratory tests, such as spirometry, can confirm the symptoms of the disease, they cannot, by themselves, confirm the diagnosis. For this, a doctor would need to make what is called a differential diagnosis. This is a process wherein all other causes of the illness have been methodically excluded. Only when the process is complete can a COPD diagnosis be considered definitive. BSIP / UIG / Getty Images Why a Differential Diagnosis Is Necessary A differential diagnosis is vital to confirming COPD, because it remains such an elusive illness. While COPD is predominantly associated with cigarette smoking, not all smokers have COPD, and not everyone with COPD is a smoker. Moreover, the symptoms and expression of the disease are highly variable. For example, a person for whom spirometry tests are inconclusive can often have severe COPD symptoms. Alternately, someone with marked impairment can often manage with few, if any, symptoms. This variability requires doctors to look at the disease differently. And, because we don't yet fully understand what triggers COPD, doctors need the safety net of a differential diagnosis to ensure the right call is made. In the course of a differential diagnosis, some of the more common investigations would include asthma, congestive heart failure, bronchiectasis, tuberculosis, and obliterative bronchiolitis. Depending on the health and history of the individual, other causes may also be explored. Asthma One of the most common differential diagnoses of COPD is asthma. In many cases, the two conditions are virtually impossible to tell apart (which can make management difficult, since the treatment courses are extremely different). Among the characteristic features of asthma: The onset of disease generally occurs early in life (compared to COPD, which happens later in life).Symptoms can vary almost daily, often disappearing between attacks.A familial history of asthma is common.Allergies, rhinitis, or eczema can often accompany it.Unlike in COPD, airflow limitation is essentially reversible. Congestive Heart Failure Congestive heart failure (CHF) occurs when the heart is unable to pump enough blood through the body to keep things functioning normally. This causes the backup of fluids in the lungs and other parts of the body. Symptoms of CHF include a cough, weakness, fatigue, and shortness of breath with activity. Among the other characteristics of CHF: Fine crackles can be heard when listening with a stethoscope.Chest X-rays will show excessive fluid and dilation of the heart muscle.Pulmonary function tests will show volume restriction (as opposed to the airflow obstruction seen in COPD). Bronchiectasis Bronchiectasis is an obstructive lung disorder that can either be congenital (present at birth) or caused by early childhood diseases such as pneumonia, measles, influenza, or tuberculosis. Bronchiectasis can exist alone or co-occur alongside COPD. Among the characteristics of bronchiectasis: Large amounts of sputum are typically produced.The person will have recurrent bouts of bacterial lung infection.Coarse crackles can be heard with a stethoscope.Chest X-ray will show dilated bronchial tubes and thickened bronchial walls.Clubbing of the fingers is common. Tuberculosis Tuberculosis (TB) is a highly contagious infection caused by the microorganism Mycobacterium tuberculosis. While TB normally affects the lungs, it can spread to other parts of the body as well, including the brain, kidneys, bones, and lymph nodes. Symptoms of TB include weight loss, fatigue, persistent cough, breathing difficulty, chest pain, and thick or bloody sputum. Among the other characteristics of TB: Disease onset can occur at any age.Chest X-rays will show lung opacities.Blood or sputum tests will confirm the presence of M. tuberculosis.The disease would typically be seen within the community or manifest as part of an outbreak. Obliterative Bronchiolitis Obliterative bronchiolitis is a rare form of bronchiolitis that can be life-threatening. It occurs when the small air passages of the lungs, known as the bronchioles, become inflamed and scarred, causing them to narrow or close. Among the other characteristics of obliterative bronchiolitis: It generally occurs at a younger age in non-smokers.There may be a history of rheumatoid arthritis or exposure to toxic fumes.A CT scan would show areas of hypodensity where the lung tissue has thinned.Airway obstruction, as measured by FEV1, may be as low as 16 percent. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. American Academy of Allergy, Asthma, and Immunology. Chronic Obstructive Pulmonary Disease (COPD). American Academy of Family Practitioners. COPD and Asthma: Differential Diagnosis. BMJ: Best Practices. COPD: Differentials. Mirza S, Clay RD, Koslow MA, Scanlon PD. COPD Guidelines: A Review of the 2018 GOLD Report. Mayo Clin Proc. 2018;93(10):1488-1502. doi:10.1016/j.mayocp.2018.05.026 NIH: National Heart Lung and Blood Institute. COPD. Vogelmeier CF, Criner GJ, Martinez FJ, et al. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary. Am J Respir Crit Care Med. 2017;195(5):557-582. doi: 10.1164/rccm.201701-0218PP