Sputum test

Last Updated December 20th, 2021

What is a sputum test?

Sputum is a thick and cloudy mucus produced by the lungs and also in other parts of the body and is a normal process. The substance can get infected by bacteria resulting in infections and resulting in a variety of complications. A sputum test involves the collection and analysis of a sample of the sputum in order to determine the nature of the organisms infecting the lungs and to follow the right course of treatment.

The major component of mucus that is produced is mucin which can act as a protective barrier or lubricant that makes many bacteria inside our bodies less dangerous. In general, the mucus protects the internal surface of the body like the lungs, stomach, and sinuses and is beneficial for our health. In case there is an infection, the mucous can take abnormal forms and its ability to act as a protective barrier reduces. One such common disease is Tuberculosis or TB that mostly affects the lungs and is caused by bacteria.

The windpipe or trachea divides and enters each lung where it is further subdivided into air channels called bronchi. Sputum gets collected into the deeper areas of the lungs and in the bronchi. A sputum test is the best way to diagnose tuberculosis and any other form of lung infection that can be caused by other kinds of bacteria.

How many people in India die as a result of tuberculosis?

India ranks #1 in the number of tuberculosis fatalities. In the year, 2016 more than 423,000 people succumbed to this disease, which made up roughly 33% of the global mortality associated with TB. Scientists now have reasons to count TB as the most infectious disease in the world, even more than HIV/AIDS. Delayed or incorrect diagnosis is a huge factor behind such shocking figures.

Why do I need to undergo a sputum test?

Your doctor can recommend a sputum test when you have one or more of the following symptoms.

– A fever for more than three days and a chronic cough lasting for more than three weeks.
– Breathing difficulties and chest pain.
– Fatigue and muscle pains.
– Loss of appetite.
– Coughing up mucus marked with blood.

The doctor may put forward a few questions regarding your cough and fever to ascertain the need for a sputum test. This may include the following.

– The duration of the cough and length of the coughing spells.
– Variation of cough patterns with the day.
– Does the cough bring up anything else?
– Whether you have lost weight, feel tired through the day or have night sweats.
– Whether you are a smoker.
– Whether you suffer from asthma.

Depending on your symptoms which may suggest an infection like bronchitis, pneumonia or tuberculosis, the doctor can order a sputum test. A respiratory tract infection can also originate from a virus or a fungus which need to be identified through tests.

How is the sputum test performed?

The sputum that is coughed up by the patient is collected in a sterilized container for the necessary testing. Ideally, the sample should be collected from a deep cough early in the morning. In some cases, more than one sample may be needed. A technician may visually check the color of the sputum that can give an idea about the type of the infection.

Off-white, yellow or green: This type of color indicates the presence of dead white blood cells and indicates that the body is fighting an infection like pneumonia or bronchitis.

Red or rusty: This can be caused due to the presence of blood in the sputum and may indicate a more serious stage of infection.

Gray or black: If you are a regular smoker or your lungs have been subjected to a severely polluted environment, the color of the sputum can become black.

In case a person is having difficulty in cough our sputum, a saline solution or a steam-like mist can be used to induce a cough. In some cases where the patient cannot cough out a sample, doctors use a device called a bronchoscope that is inserted inside the windpipe to collect a sample.

Certain drugs are given to the patient that helps them to relax before the use of a bronchoscope but the procedure can result in a sore throat or some minor bleeding. For those who are extremely sick, a soft, flexible tube is inserted through the nose and down the throat. After that, a sputum sample is collected through suction.

The sample generally undergoes two types of tests, smear, and culture. A part of the sample is smeared on a glass slide and a special stain is added that will make any TB-causing bacteria show up under a microscope. Another section of the collected sample is placed on a special culture dish and the growth of bacteria and other organisms are observed.

This helps to separate the disease-causing germs from the friendly ones present in the body. This is a step-by-step identification process that involves multiple biochemical tests and observations of the organism’s growth characteristics. It also helps to determine the type of antibiotic that will be best suited to treat the disease.

What is the price for a sputum test in India?

The test is conducted in private hospitals and clinics and the cost ranges from Rs. 800 to 1600.

When will I get the test results?

The smear test results are available within 1 to 2 working days depending on the clinic. The culture test results take more time as it depends on the bacterial growth rate and can take up to 2or more weeks in some cases.

What is the normal range for the sputum test?

Sputum specimens are observed for mucopurulent strands, leukocytes, and blood and culture results. A trained laboratorian differentiates harmless microbes from pathogenic bacteria and identifies the various types of bacteria present in the culture. In a normal sputum sample, no disease-causing germs will be detected. A culture that is reported as “no growth in 24 or 48 hours” is usually considered negative. A positive result indicates the presence of TB or other disease-inducing bacteria.

What do the results mean?

An abnormal sputum sample is marked as positive and can indicate any of the following conditions depending on the infecting organism.

– Swelling of the air passageways indicating bronchitis.
– Tuberculosis
– Pneumonia
Lung abscess
– A flare-up of chronic obstructive pulmonary disease (COPD) or cystic fibrosis.
The doctor will prescribe a suitable course of treatment after the disease has been identified. A further full blood count test or a blood culture test can also be conducted to determine the exact nature of the infection. In some cases, a normal sputum test cannot identify certain virus and fungi responsible for the ailment. The doctor may have to advise a different course of action if no bacteria is detected but the symptoms persist.

Do I need to fast for the sputum test?

The sputum test does not need any fasting but patients are advised not to eat anything few hours before the sample is collected (in the morning) as it may contaminate the sputum sample.

What else do I need to know before I test my Sputum test?

Try to spit out as much as sputum as possible with the minimum amount of saliva.Provide a sputum sample with light coughing. Deep cough before providing the sample.
The collection should be done in a special area away from the others present.Eat anything just before the sputum test sample collection.
Drinking lots of water and other fluids can help in the collection process.Forget to rinse your mouth before giving the sputum sample.

In case the observation of the sample reveals the presence of more normal squamous epithelial cells from the mouth, a recollection may be necessary. A sample with more white blood cells that have been exposed to the infection is considered as a better choice for culturing.

Can pregnant women undergo a sputum test?

The test is safe and pregnant women can appear for it without restrictions.

Is the sputum test possible for new-born babies?

Babies and children are unable to cough out sputum that is necessary for the test. Your doctor can guide you in finding the best methods for getting them tested for lung infections.

How common are lung diseases in India?

As per the latest statistics, India contributes to 32% of the global burden of respiratory diseases. This majorly includes asthma and COPD. In 2016, 55.3 million people were estimated to be suffering from COPD in India. More than half of the respiratory illnesses can be attributed to poor air quality.

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