Sputum Culture

A sputum culture is a test that looks for bacteria or other organisms that may cause an illness in your lungs or the airways that lead to your lungs. Sputum, commonly known as phlegm, is a thick mucus produced by your lungs. If you have an infection or a persistent sickness that affects your lungs or airways, you may cough up phlegm.

Sputum is distinct from spit or saliva. Sputum includes immune system cells that aid in the battle against bacteria, fungi, and other foreign items in your lungs or airways. The thickness of sputum aids in the trapping of foreign particles. This permits cilia (tiny hairs) in the airways to push it into the mouth and out through the coughing reflex.

Sputum can come in a variety of hues. The colour of sputum can help you determine what sort of infection you have or whether a chronic ailment has worsened:


This normally indicates that there is no disease present, but significant quantities of clean sputum may indicate lung disease.

Gray or white

This is also normal, but excessive levels may indicate lung illness.

Green or dark yellow

This frequently indicates a bacterial infection, such as pneumonia. Yellowish-green sputum is also prevalent in cystic fibrosis patients.


This is frequently seen among smokers. It is also a symptom of black lung disease. Black lung disease is a dangerous ailment that can develop after prolonged exposure to coal dust.


This might indicate pulmonary edema, a disease where excess fluid accumulates in the lungs. In persons with congestive heart failure, pulmonary edema is prevalent.


This might be a precursor to lung cancer. It might also indicate a pulmonary embolism, a potentially fatal disorder in which a blood clot from the leg or another region of the body breaks free and travels to the lungs.

Alternative names: respiratory culture, bacterial sputum culture, routine sputum culture

What is the use of sputum culture?

A sputum culture is commonly used to:

  • Identify bacteria or fungi that may be causing a lung or airway infection.
  • Check to see if a chronic lung disease has become worse.
  • Check to see whether your infection therapy is working.

A Gram stain is frequently used in conjunction with a sputum culture.

What is the need for a sputum culture?

If you have signs of pneumonia or any serious infection of the lungs or airways, you may require this test. These are some examples:

What happens during a sputum culture?

A sample of your sputum will be required by your doctor. During the examination:

  • A healthcare practitioner will guide you to take a deep breath and cough into a particular cup.
  • To assist in releasing sputum from your lungs, your physician may tap you on the chest.
  • If you're having difficulties coughing out enough phlegm, your doctor may suggest inhaling a salty mist to help you cough more deeply.
  • If you can still cough up enough sputum, your physician may do a bronchoscopy. With this process, you will be given a relaxing numbing medication to prevent pain.
  • A small, illuminated tube will then be inserted via mouth or nose and into your airways.
  • A little brush or suction will be used by your physician to obtain a sample from your airway.

How to prepare for the test?

Before the sample is taken, you may need to rinse your mouth with water. If you are scheduled for a bronchoscopy, you may be requested to fast (not eat or drink) for one to two hours before the procedure.

Is there any risk in the test?

There is no danger in putting a sputum sample in a container. If you underwent a bronchoscopy, your throat might be slightly painful afterward.

What do the findings imply?

If your findings were normal, it implies that no potentially hazardous bacteria or fungi were discovered. If your findings are abnormal, you may have a bacterial or fungal infection. Further tests may be required by your provider to determine the precise sort of illness you have. The most prevalent types of pathogenic bacteria discovered in sputum cultures include:

A positive sputum culture result might indicate a flare-up of a chronic illness such as cystic fibrosis or chronic obstructive pulmonary disease (COPD).

Important information to know about sputum cultures?

Sputum is sometimes known as phlegm or mucus. Although all of the phrases are valid, sputum and phlegm exclusively apply to mucus produced in the respiratory system (lungs and airways). Mucus is a sort of sputum (phlegm). Mucus can also be produced in other parts of the body, such as the urinary or vaginal tract.

Frequently Asked Questions

1. What is a sputum culture test?

A sputum culture test is a laboratory test that is used to detect and identify the presence of bacteria, viruses, or fungi in a sample of sputum (mucus) that is coughed up from the lungs.

2. Why is a sputum culture test done?

A sputum culture test is usually done to diagnose a respiratory infection, such as pneumonia, bronchitis, or tuberculosis. It is also used to monitor the effectiveness of antibiotic treatment for a respiratory infection.

3. How is a sputum culture test performed?

A sputum culture test requires a sample of sputum, which is typically collected by coughing up phlegm from the lungs into a sterile container. The sample is sent to a lab for analysis, where it is cultured to identify the presence of bacteria, viruses, or fungi.

4. How do I prepare for a sputum culture test?

You may be asked to avoid eating or drinking anything for a few hours before the test to ensure that the sample is as pure as possible. Your doctor may also ask you to brush your teeth and rinse your mouth with water before collecting the sample.

5. Is a sputum culture test painful?

No, a sputum culture test is not painful. However, some people may find it uncomfortable to cough up sputum.

6. How long does it take to get the results of a sputum culture test?

The results of a sputum culture test can take several days to a week to be processed and analyzed. Your healthcare provider will inform you of the results once they are available.

7. What are the risks associated with a sputum culture test?

There are no significant risks associated with a sputum culture test. However, some people might experience mild discomfort or nausea while coughing up sputum. Additionally, there is a small risk of infection if the sample is not collected or handled properly.

8. What is the cost of a sputum culture test?

The cost of a sputum culture test is approximately Rs. 280 to Rs. 600. The price can differ from place to place.

9. Where can I get a sputum culture test?

You can get a sputum culture test at Medicover Hospitals.