Sputum examination is a type of clinical analysis in which different characteristics of sputum are assessed, such as fluidity, color and, especially, whether there are a large number of bacteria that may be causing an infection in the lung.
Thus, this type of examination is normally used by the pulmonologist to confirm the diagnosis of some respiratory infections, such as:
- Pneumonia; Tuberculosis; Bronchitis; Cystic fibrosis.
Often, the sputum test can be ordered even when there is already a diagnosis of an infection in the lung to identify the bacteria or other microorganism that is causing it, allowing a better adaptation of the treatment, with a more specific antibiotic, for example.
See the main symptoms that can lead the doctor to suspect tuberculosis, pneumonia or bronchitis.
How the exam is done
The sputum test is very easy to do, it is only necessary to put the phlegm in a small plastic cup. To ensure that the collected sputum contains the bacteria that are in the lung, it is advisable to make a deep cough to loosen the secretions that are in the lung, avoiding only collecting saliva from the mouth and upper airways.
If there is difficulty in extracting the sputum, the pulmonologist can give a light pat on the back to help the secretion release from the lung walls and up to the mouth. Generally, collection should be done in the morning before eating or drinking, to avoid contaminating the sputum sample.
In some people, the doctor may even recommend doing a bronchoscopy to be able to collect the necessary amount of lung sputum. Understand what bronchoscopy is and how it is done.
How to prepare for the exam
There is not a very specific preparation for the sputum exam, however, some doctors may recommend washing your mouth with plain water before coughing and avoid using mouthwashes before the exam.
How to interpret the results
The results of the sputum test should always be interpreted by the pulmonologist, but they are usually:
- Negative: it is the normal result and means that no bacteria or fungi have been found that can cause disease. Positive: means that bacteria or fungi have been found that can cause disease in the sputum sample. In these cases, the type of microorganism is also usually indicated to help the doctor choose an antibiotic or antifungal.
In the case of a negative result, it is very important that the test is still evaluated by the pulmonologist since, if there are symptoms, it may mean that there is an infection caused by viruses that are not identified in the test.
Check how the treatment is done in cases of the most common infections such as pneumonia and tuberculosis.
