How do You Collect a Sputum Sample?

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  • Written By: Jacob Queen
  • Edited By: Lauren Fritsky
  • Last Modified Date: 22 October 2019
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Sputum is usually a combination of saliva and mucus that forms in a person's lungs. To collect a sputum sample, doctors generally have the patient cough deeply and spit into a cup. There are often some precautions taken to avoid any contamination of the sample, and sometimes the patient has to drink extra fluid to increase the quantity of the lung secretion. In other situations, doctors have to suck out the sputum through a tube inserted into the nose that runs back to the throat. This method is especially common for patients who are too severely ill to cough up their own samples—sometimes, doctors may even have to take those samples with a syringe inserted through the throat.

When taking a sputum sample, doctors sometimes ask the patient to cleanse her mouth first. This is often done very carefully to avoid adding any chemicals to the sample. Chemicals can sometimes kill bacteria or viruses, and the whole purpose of collecting sputum samples is usually to see if there is anything foreign living inside someone’s lungs. The safest way to cleanse the mouth is typically to rinse with water.


After they collect the sputum, doctors will generally use portions of the samples to test for various infections. This is done by putting sputum on foods that different kinds of bacteria and other foreign invaders like to eat. If anything grows on these foods, it tells the doctors what kind of infection the patient is suffering from. This can be useful for doctors when determining best treatment approaches for someone with a respiratory illness. It’s sometimes especially necessary when the illness is mysterious and isn’t responding to normal treatment measures.

Sometimes patients can have a hard time coughing up a good sputum sample. In those situations, doctors may ask the patients to drink some water and then come back in an hour or so for another attempt. Dehydration is one of the most common problems when collecting sputum because it lessens the available fluid in the lungs. Drinking water is generally the most obvious way to deal with this problem, but there are also others.

Doctors will sometimes insert a tube into the breathing passage to directly add fluid to the lungs. This fluid generally mixes with dried up mucus, and when the patient coughs it up, it’s basically equivalent to a normal sputum sample. This procedure can sometimes be somewhat uncomfortable, so doctors will usually sedate patients first.


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Post 4

@shell4life – I would much rather drink a lot of water myself instead of having it injected! This is probably what most people do.

I think that a lot of elderly patients have to have a tube inserted either in their nose or throat to collect sputum. They wouldn't be strong enough to handle the anesthesia and extreme coughing that being put under and having fluid injected would bring.

The sad thing is that many elderly people who are bedridden actually get pneumonia because they are unable to cough up their own mucus that drains down into the lungs. It would be horrible to have pneumonia and have no way of getting rid of the phlegm.

Post 3

My dad went to his doctor when he was having symptoms of pneumonia. He had a constant cough and was having trouble getting a good breath.

He had been coughing up sputum, but he had just been swallowing it. So, the first time he saw it was when it landed in the cup at the doctor's office.

It was pink and frothy. This scared him, because he knew it meant it had blood in it.

Post 2

I've never heard of putting someone to sleep for a sputum test. I can't imagine having to have fluid injected into my lungs just to cough up some sputum!

Luckily, I've always been able to cough into the cup. The doctor pounds on my back while I'm coughing, and this loosens things up to make coughing easier.

Post 1

I didn't know that water would help a doctor collect a sputum culture. I've always heard you should drink a lot of fluids when you are sick, but I didn't know this would make you cough up more sputum!

I know it's supposed to be a good thing when you cough it up, because you are removing it from your lungs. However, when your body is absolutely fatigued from coughing all the time, it can be hard on you.

I've had bronchitis before, and my lungs and stomach both ached from all the constant coughing. My doctor wanted me to take an expectorant, but I refused, because I just could not stand to cough anymore than I already was.

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