Asthma Lexicon: Sputum Terms To Know

So, this is kind of a gross topic. But, when you have asthma, it’s good to know about asthma sputum. What you’re spitting up can say a lot about what’s going on inside your lungs.

So, here’s what to know about sputum

Mucus. This is a sticky, slimy substance secreted by goblet cells lining airways. It contains mostly water. It lubricates airways. It prevents airways from drying out. It also traps unwanted particles and pathogens. It’s part of your immune system to keep your lungs free and clear of germs. Along with water, mucus also contains mucin. 1-2

Mucin. It’s a sticky protein. It makes mucus sticky. So, when it mixes with water, it makes it sticky. Therefore, it’s the main ingredient your body uses to make mucus. 1-2Goblet cells. These are cells randomly scattered along airways. They store mucus. They secrete mucus when needed. As part of airway remodeling, asthmatics may have an abnormally large amount of goblet cells. 3

Hypersecretion. This is when goblet cells overproduce mucus. It may be because asthmatics tend to have more goblet cells than normal. It may also occur as part of the asthma response. Exposure to asthma triggers causes goblet cells to overproduce mucus. 2

obstruction. Along with bronchospasm, excessive mucus may cause airways to become narrowed. This “obstructs” the flow of air through airways. This can make you feel short of breath. It may also make you cough (defined below).

Mucus plug. It’s when mucus gets thick and blocks airways. It’s a thick, sticky block of mucus. It may occur during acute and severe asthma attacks. It may occur due to hypersecretion. They may also be caused by an increase in white blood cells called eosinophils in asthmatic airways.4-5

Secretions. Another term for lots of phlegm in your airways. It may produce lung sounds called crackles or rhonchi.

Sputum. It’s a term for sputum when it’s present in large amounts. It’s what mucus is called when it enters your upper airway. It contains a mixture of both mucus and saliva. It’s what you cough up, swallow, or spit up.

Phlegm. Another term for sputum.

A cough. When moved to the back of your throat, phlegm may trigger the cough reflex. This is what makes you forcibly move air through your vocal cords. This can help dislodge and move up sputum further up your airway. This allows you to either spit it up or swallow it. Swallowed phlegm is destroyed by stomach acids.3

Increased mucus can be a symptom of asthma. So, this makes a cough one of the more common signs of asthma. The sputum you cough up can help a doctor diagnose what’s triggering your asthma. So, your doctor may want a sample.

Sputum Induction. This is where your doctor has you produce a sputum sample.

Sputum Sample. You will be given a cup that is sterile inside. It’s best that you take precautions when removing the lid. You don’t want to accidentally contaminate it with germs from your environment. You will want to generate a sample from deep inside your lungs. Spit it into the cup. Place the lid securely on top.

Expectorate. This is a fancy term that means “to spit out phlegm. It means to remove phlegm from your airways by spitting it out. You’ll need to do this to produce a sputum sample.

Laboratory tech. A laboratory will collect your sputum sample. This person will run tests on your sputum. This will determine if it is contaminated with bacteria. If a bacteria is present, your doctor may order an antibiotic.

What to make of this? We asthmatics are often asked to produce sputum samples. We are exposed to a variety of terms, such as those listed above. Now you know what they mean.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.
View References
  1. Tortora, Gerald J., Bryan Derrickson, “Principles Of Anatomy And Physiology,” 15th edition, 2017, Wiley, pages 40, 78-79, 104, 111, 113, 115, 135
  2. Harrison, TR, et al., editors, “Harrison’s Principles And Practice Of Medicine,” 19 Edition, 2015, McGraw, pages 243-244
  3. Rogers, Duncan F., “Airway Goblet Cell Hyperplasia in asthma: hypersecretory and anti-inflammatory,” Wiley Online Library, 2002, August 19,, accessed 8/4/18
  4. Dunican, et al, “Mucus Plugs In Patients With Asthma Linked To Eosinophilia And Airflow Obstruction,,, accessed 8/4/18
  5. Fanta, C.H., “Clinical aspects of mucus and mucus plugging in asthma,” Journal of Asthma, 1985,, accessed 8/4/18
  6. Hays, Steven R., John V. Fahy, “The Role of Mucus In Fatal Asthma,” The American Journal Of Medicine, July, 2003, J, accessed 8/4/18


View Comments (4)
  • Shellzoo
    3 months ago

    I always seem to cough up a fair amount of sputum in the morning after using my Advair. Sometimes it even feels hard to use my inhaler because of all the sputum I can’t quite cough up. It makes sense that asthmatics can over produce sputum. I already knew the terms but it was fun reading the article. Good reminder to be aware of what you are coughing up.

  • SamuelTaylor moderator
    3 months ago

    We are glad that you liked the article. I used to get the same thing when I was using Advair. It never got that bad, so it never bothered me. I’m sorry to hear that it is more of an issue for you. What do you normally do to manage the sputum?

    I wish you well,
    Samuel, Team

  • Leon Lebowitz, RRT moderator
    3 months ago

    Hi again, Shellzoo and thanks for sharing with the community what works for you. It sounds like you have a good and practical approach to this for yourself. Keep up the good work! Leon (site moderator)

  • Shellzoo
    3 months ago

    I do a couple things. I drink lots of fluids in the am to loosen the secretions and rehydrate. I also cough what I can up since it is better out than in my airway. I find my allergy meds that I take at night dehydrate me just enough so my sputum seems thick in the morning. The extra fluids seem to help.

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