Table of ContentsView AllTable of ContentsPhysical ExaminationLabs and TestsImagingDifferential DiagnosisFrequently Asked QuestionsNext in Pneumonia GuideHow Pneumonia Is Treated
Table of ContentsView All
View All
Table of Contents
Physical Examination
Labs and Tests
Imaging
Differential Diagnosis
Frequently Asked Questions
Next in Pneumonia Guide
Pneumoniaaffects millions of people every year. According to the Centers for Disease Control and Prevention (CDC), more than 400,000 people require evaluation and treatment in an emergency department and more than 50,000 people die from the disease.But complications can be prevented.
Finding out you have pneumonia is the first step, then learning what type of pneumonia you have—bacterial,viral, orfungal—is essential for propertreatment. Note that diagnostic steps may vary for people who are generally healthy and develop symptoms (community-acquired pneumonia) compared to those who are in a hospital or other healthcare setting.
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Using a stethoscope, a practitioner will listen to your lungs. They are listening to crackling sounds orwheezing. Decreased sounds in one area could mean thatpneumonia has formedthere. Tapping on your back over that area may help to determine the extent of infection or if there is an associated fluid collection.
Do not be surprised if you are asked to say the letter “E” out loud. If you have fluid in your lungs, it will sound like “A” when listening through the stethoscope.
While the physical exam can raise suspicion for pneumonia, the diagnosis can be strengthened using a variety of tests. Your healthcare provider may or may not use the following tests. Know that most are simple and straightforward on your part—a simple blood draw or sample collection, quick and painless.
Complete Blood Count
A complete blood count is a simple and inexpensive test. Awhite blood countis one of the blood counts measured. If it is elevated, infection or inflammation is present.It does not specifically let you know if you have pneumonia.
Procalcitonin
Results are usually positive within four hours of bacterial infection and peak within 12 to 48 hours. While it does not let you know what type of bacteria is present, it indicates that antibiotic treatment may be necessary.
The use of procalcitonin is still being explored in the diagnosis of community-acquired pneumonia and is not currently a routine blood test for every person with symptoms of pneumonia.
Sputum Culture and Gram Stain
If you are an outpatient, your healthcare provider may not order a sputum culture to identify whether you have bacterial pneumonia and the causative organism. However, if you are hospitalized and develop pneumonia symptoms, they may order a sputum culture.
Unfortunately, collecting a good-quality sputum sample can be difficult, especially if someone has a dry cough. It often gets contaminated with normal bacteria that live in the respiratory tract.
A sample should be collected before you are treated with antibiotics. You’ll be asked to cough up some sputum with as little saliva as possible. If you are having trouble doing so, a healthcare provider may use a device with a light and tiny camera placed down your throat. They will help relax you with medications during the procedure, and there are few side effects outside of a potential slightly sore throat.
Once collected, aGram stainis applied to part of the specimen and examined under a microscope. A good-quality sputum sample will show several white blood cells but few epithelial cells. Bacteria will appear red or violet and, based on their appearance, can be categorized as one of two classes of bacteria. Narrowing the diagnosis makes it easier to choose an appropriate antibiotic.
To find out what specific bacteria is causing your illness, your sample will be cultured in Petri dishes. Once the bacteria or fungi grow, it is tested against different antibiotics to see what treatments will be most effective.
The problem is that it may take days to get a definitive culture result. Also, certain bacteria likeS. pneumoniaeare difficult to grow and can give false-negative results. Because of the challenges in getting a good-quality sample, this test is more commonly used for people in the hospital rather than those living in the community.
Urine Antigen Tests
Urine antigen tests are not routinely ordered for outpatients who have symptoms of pneumonia, but they may be ordered for people who develop pneumonia symptoms in a hospital setting.
The results are rapidly available and studies have shown them to be more accurate than Gram stain or culture. Another advantage of the test is that treatment with antibiotics will not alter the results.
The problem is that urine antigen tests are less accurate in milder cases of pneumonia. It also only tests for one serotype ofLegionellaalthough there are many species. Also, unlike with culture, there is no way to use the results to determine what antibiotics would be most effective for treatment.
Serology
Serologic tests are not routine for pneumonia for outpatients but may be ordered for people who develop pneumonia symptoms in the hospital.
Some bacteria are difficult to grow in culture and do not have a urine antigen test available for screening.Chlamydia,Mycoplasma, and someLegionellaspecies are atypical bacteria that fall into this category.
There are serologic blood tests that may be able to determine when and if you have been infected.Serology measures antibodies formed against a specific pathogen. IgM antibodies indicate a new infection whereas IgG antibodies usually show that you have been infected in the past. It can sometimes be difficult to know when IgM antibodies transitioned to IgG antibodies.
PCR and Enzyme Immunoassays
It can be difficult to culture a virus. Instead, viral infections are more commonly diagnosed using polymerase chain reaction (PCR) and enzyme immunoassays. To perform any of these tests, a sample must be collected. Depending on what virus is being considered, this sample can be blood, sputum, nasal secretions, or saliva.
Enzyme immunoassays, however, can be performed as a point of care test with results available in 15 minutes to an hour. These immunoassays use antibodies to detect the presence of specific viral antigens and can screen for multiple viruses at one time.
Pneumonia is a common complication of COVID-19. ForCOVID-19 testing, the most accurate specimen is collected from the nose. This is the part of the upper respiratory tract where concentrations of the virus may be greatest. A flexible six-inch cotton swab is inserted into the nose and along the back of your throat where it is left in place for 15 seconds.
The same swab is then inserted into the other nostril to maximize how much mucous is collected for the test. Studies are then performed to assess if genetic material from the virus is present.
Imaging studies are often performed before laboratory tests. If you are otherwise healthy, a healthcare provider may treat you for pneumonia based on physical exam and imaging studies alone.
Chest X-Ray
If pneumonia is suspected based onsymptomsand physical exam, the standard of care is to get achest X-ray. A chest X-ray may show an infiltrate, which is a collection of pus, blood, or protein in the lung tissue. It can also reveal other signs of lung disease like cavitations andpulmonary nodules.
CT Scan
Bronchoscopy
In severe cases that do not respond to therapy, your healthcare provider may pursue further imaging to look for other causes. This evaluation may includebronchoscopy, where a thin camera is guided through your nose or mouth down into your lungs.
Bronchoscopy visualizes big airways (trachea or windpipe and large bronchi)—not lungs. Your practitioner may decide to take some fluid from your airway for culture if your phlegm culture is negative and you are immunosuppressed or if you have a chronic illness requiring a precise diagnosis of the cause of your pneumonia. Bronchoscopy is almost never done in an otherwise healthy adult withcommunity-acquired pneumonia.
There are other conditions that can have symptoms similar to pneumonia, likebronchitisorcongestive heart failure. If someone hasasthma,bronchiectasis, or chronic obstructive pulmonary disease(COPD), it could be a flare-up of their known lung disease. In the worst-case scenario, it could be a warning sign oflung cancer.
How Pneumonia Is Treated
Frequently Asked QuestionsIt is recommended that any suspected case ofpneumoniabe confirmed with an X-ray. If the X-ray is inconclusive or more information is needed, other tests may be ordered, such as a CT scan. However, in some cases, a practitioner may prescribe antibiotics based on symptoms and a physical exam without a chest X-ray.Yes. There are other conditions with similar symptoms, some of which can be differentiated with a chest X-ray, blood tests,pulmonary functions tests (PFTs), and other investigations. These include:Acute bronchitisAsthmaBronchiolitis obliteransCongestive heart failureCOPDEndocarditisLung abscessLung cancerPulmonary embolismYou may be asked to cough into a specimen cup to provide a sample of phlegm to be tested.If you’re unable to cough up a sample, your healthcare provider may perform abronchoscopyin which a tube is inserted into your airway and a sample is sucked or swabbed out.
It is recommended that any suspected case ofpneumoniabe confirmed with an X-ray. If the X-ray is inconclusive or more information is needed, other tests may be ordered, such as a CT scan. However, in some cases, a practitioner may prescribe antibiotics based on symptoms and a physical exam without a chest X-ray.
Yes. There are other conditions with similar symptoms, some of which can be differentiated with a chest X-ray, blood tests,pulmonary functions tests (PFTs), and other investigations. These include:Acute bronchitisAsthmaBronchiolitis obliteransCongestive heart failureCOPDEndocarditisLung abscessLung cancerPulmonary embolism
Yes. There are other conditions with similar symptoms, some of which can be differentiated with a chest X-ray, blood tests,pulmonary functions tests (PFTs), and other investigations. These include:
You may be asked to cough into a specimen cup to provide a sample of phlegm to be tested.If you’re unable to cough up a sample, your healthcare provider may perform abronchoscopyin which a tube is inserted into your airway and a sample is sucked or swabbed out.
9 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Pneumonia.Regunath H, Oba Y.Community-acquired pneumonia. In:StatPearls [Internet].Chmielewski PP, Strzelec B.Elevated leukocyte count as a harbinger of systemic inflammation, disease progression, and poor prognosis: a review.Folia Morphol (Warsz).2018;77(2):171-8. doi:10.5603/FM.a2017.0101Meisner M.Update on procalcitonin measurements.Ann Lab Med.2014;34(4):263-73. doi:10.3343/alm.2014.34.4.263MedlinePlus.Sputum culture.Andrade DC, Borges IC, Ivaska L, et al.Serological diagnosis of pneumococcal infection in children with pneumonia using protein antigens: A study of cut-offs with positive and negative controls.J Immunol Methods.2016;433:31-7. doi:10.1016/j.jim.2016.02.021Centers for Disease Control and Prevention.Overview of yesting for SARS-CoV-2 (COVID-19).Wootton D, Feldman C.The diagnosis of pneumonia requires a chest radiograph (X-ray)–yes, no or sometimes?Pneumonia. 2014;5(S1):1-7. doi:10.15172/pneu.2014.5/464Black AD.Non-infectious mimics of community-acquired pneumonia.Pneumonia (Nathan). 2016;8:2. doi:10.1186/s41479-016-0002-1
9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Pneumonia.Regunath H, Oba Y.Community-acquired pneumonia. In:StatPearls [Internet].Chmielewski PP, Strzelec B.Elevated leukocyte count as a harbinger of systemic inflammation, disease progression, and poor prognosis: a review.Folia Morphol (Warsz).2018;77(2):171-8. doi:10.5603/FM.a2017.0101Meisner M.Update on procalcitonin measurements.Ann Lab Med.2014;34(4):263-73. doi:10.3343/alm.2014.34.4.263MedlinePlus.Sputum culture.Andrade DC, Borges IC, Ivaska L, et al.Serological diagnosis of pneumococcal infection in children with pneumonia using protein antigens: A study of cut-offs with positive and negative controls.J Immunol Methods.2016;433:31-7. doi:10.1016/j.jim.2016.02.021Centers for Disease Control and Prevention.Overview of yesting for SARS-CoV-2 (COVID-19).Wootton D, Feldman C.The diagnosis of pneumonia requires a chest radiograph (X-ray)–yes, no or sometimes?Pneumonia. 2014;5(S1):1-7. doi:10.15172/pneu.2014.5/464Black AD.Non-infectious mimics of community-acquired pneumonia.Pneumonia (Nathan). 2016;8:2. doi:10.1186/s41479-016-0002-1
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Pneumonia.Regunath H, Oba Y.Community-acquired pneumonia. In:StatPearls [Internet].Chmielewski PP, Strzelec B.Elevated leukocyte count as a harbinger of systemic inflammation, disease progression, and poor prognosis: a review.Folia Morphol (Warsz).2018;77(2):171-8. doi:10.5603/FM.a2017.0101Meisner M.Update on procalcitonin measurements.Ann Lab Med.2014;34(4):263-73. doi:10.3343/alm.2014.34.4.263MedlinePlus.Sputum culture.Andrade DC, Borges IC, Ivaska L, et al.Serological diagnosis of pneumococcal infection in children with pneumonia using protein antigens: A study of cut-offs with positive and negative controls.J Immunol Methods.2016;433:31-7. doi:10.1016/j.jim.2016.02.021Centers for Disease Control and Prevention.Overview of yesting for SARS-CoV-2 (COVID-19).Wootton D, Feldman C.The diagnosis of pneumonia requires a chest radiograph (X-ray)–yes, no or sometimes?Pneumonia. 2014;5(S1):1-7. doi:10.15172/pneu.2014.5/464Black AD.Non-infectious mimics of community-acquired pneumonia.Pneumonia (Nathan). 2016;8:2. doi:10.1186/s41479-016-0002-1
Centers for Disease Control and Prevention.Pneumonia.
Regunath H, Oba Y.Community-acquired pneumonia. In:StatPearls [Internet].
Chmielewski PP, Strzelec B.Elevated leukocyte count as a harbinger of systemic inflammation, disease progression, and poor prognosis: a review.Folia Morphol (Warsz).2018;77(2):171-8. doi:10.5603/FM.a2017.0101
Meisner M.Update on procalcitonin measurements.Ann Lab Med.2014;34(4):263-73. doi:10.3343/alm.2014.34.4.263
MedlinePlus.Sputum culture.
Andrade DC, Borges IC, Ivaska L, et al.Serological diagnosis of pneumococcal infection in children with pneumonia using protein antigens: A study of cut-offs with positive and negative controls.J Immunol Methods.2016;433:31-7. doi:10.1016/j.jim.2016.02.021
Centers for Disease Control and Prevention.Overview of yesting for SARS-CoV-2 (COVID-19).
Wootton D, Feldman C.The diagnosis of pneumonia requires a chest radiograph (X-ray)–yes, no or sometimes?Pneumonia. 2014;5(S1):1-7. doi:10.15172/pneu.2014.5/464
Black AD.Non-infectious mimics of community-acquired pneumonia.Pneumonia (Nathan). 2016;8:2. doi:10.1186/s41479-016-0002-1
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