Sputum eosinophil test
Quick answer: This test looks for eosinophils, a type of white blood cell linked to allergy, in a sputum (phlegm) sample. It may be used when asthma or an allergic lung condition is suspected.
- SampleSputum
- TakesAbout 5 to 10 minutes
- Before the testA deep-cough sample, often first thing in the morning, is usually requested; rinse your mouth with plain water first.
How the test is done
- 1You rinse your mouth with plain water first
- 2You take a deep breath and cough hard to bring up phlegm from your chest
- 3You spit it into a sterile container, keeping saliva out as far as possible
- 4The lab stains a smear and counts eosinophils under a microscope
What your results can mean
Reading your report
Your doctor will read the result together with your symptoms and other tests.
If the result is outside the usual range
Raised eosinophils in sputum can be seen with allergic asthma and some other allergic or parasitic lung conditions. Low or absent eosinophils can suggest the airway inflammation is of another type.
Who usually has this test
People with asthma, long-lasting cough or wheeze, where doctors want to know the type of airway inflammation.
Risks and aftercare
There are no risks, though coughing may leave your throat slightly sore.
Names and options
Also called: eosinophils in sputum, sputum eosinophil count
Listed by the hospital as
- EOSINOPHILS, SPUTUM
Questions about this test
Is an early morning sputum sample easier to give?
Yes, phlegm builds up overnight, so a sample on waking is usually easier to cough up. Rinse with plain water first rather than brushing with toothpaste just before.
What if I cannot cough up phlegm?
Tell the staff. They may suggest steam or salt-water inhalation to help bring up a sample.
Is a sputum eosinophil test the same as a blood eosinophil count?
No. The blood count shows eosinophils across the body, while sputum shows what is happening in the airways. The two results can differ.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.