Test Overview
Sputum
cytology examines a sample of sputum (mucus) under a microscope to determine
whether abnormal cells are present. Sputum is not the same as saliva. Sputum is
produced in the lungs and in the airways leading to the lungs. Sputum has some
normal lung cells in it.
Sputum cytology may be done to help detect
certain noncancerous lung conditions. It may also be done when
lung cancer is suspected.
A sputum sample
may be collected:
- By a person coughing up mucus.
- By
breathing in a saltwater (saline) mist and then coughing.
- During
bronchoscopy, which uses a bronchoscope to look at the
throat and airway.
Why It Is Done
Sputum cytology is done to
find:
- Lung cancer. But sputum cytology is not used as a
screening test for people at risk for developing lung cancer, such as
smokers.
- Noncancerous lung conditions, such as
pneumonia or inflammatory diseases,
tuberculosis, or the buildup of asbestos fibers in the
lungs (asbestosis).
How To Prepare
Home or office sample
No special preparation is
required if the sputum sample is to be collected at home or in your doctor's
office.
Bronchoscopy sample
Before you have bronchoscopy
to collect a sputum sample, tell your doctor if you:
- Are taking any medicines.
- Have
allergies to any medicines, including
anesthetics.
- Take a blood thinner, or if you have had bleeding problems.
- Are or
might be pregnant.
If you have a bronchoscopy, you will be asked to sign a consent form that says you understand the risks of the test and agree to have it done.
Talk to your doctor about any concerns you have regarding the
need for the test, its risks, how it will be done, or what the results will
mean. To help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
Your doctor will tell you how soon
before the procedure to stop eating and drinking. Follow the instructions exactly about when to stop eating and drinking, or your procedure may be canceled. If your doctor has instructed you to take your medicines on the day of procedure, please do so using only a sip of water.
Arrange to have someone drive you home after the
procedure.
How It Is Done
Home or office sample
Three sputum samples are
usually collected over 3 days. Your doctor will give you a container to collect
the sputum. This container may have a small amount of liquid (called fixative)
in it. The fixative helps preserve the sample. Do not drink this liquid.
For best results, collect the sample in the morning right after waking
up. Follow these steps:
- If you wear dentures, remove them before
collecting the sample.
- Rinse your mouth with
water.
- Take about four deep breaths followed by a few short coughs,
then inhale deeply and cough forcefully into the container. Sputum is not the
same as saliva, so make sure to get a sample of mucus from deep in your
airway. Collecting the sample in the
morning, when you first wake up, is generally best.
- If you have
trouble obtaining a good sample, try taking a hot shower first to help loosen
the mucus in your airway.
Carefully follow your doctor's instructions about where
to deliver the sample. You may be instructed to take the sample to the doctor's
office or to a laboratory. Deliver the sample soon after you obtain it. You may
be instructed to refrigerate the sample if you are not able to deliver it
immediately.
Bronchoscopy sample
During bronchoscopy, a thin, lighted instrument (bronchoscope) is inserted through the nose or mouth into the throat and then into the airways leading to the lungs.
To learn more about how the procedure is done, see the topic
Bronchoscopy.
How It Feels
Home or office sample
If you have discomfort when taking a deep
breath or coughing, getting a sputum sample may be uncomfortable.
Bronchoscopy sample
You may be able to feel pressure in your airway as the bronchoscope is moved from place to place. You may gag or cough. To learn more about how the procedure feels, see the topic Bronchoscopy.
Risks
Home or office sample
There is no risk linked
with collecting a sputum sample at home or at your doctor's office.
Bronchoscopy sample
Bronchoscopy is generally a
safe procedure. Although complications are rare, you should discuss the risks
in your particular case with your doctor. Complications that may occur
include:
- Spasms of the bronchial tubes. These can
impair breathing.
- Irregular heart rhythms
(arrhythmias).
- Infection, such as pneumonia. These usually can be
treated with antibiotics.
Results
Sputum cytology examines a sample of
sputum (mucus) under a microscope to determine whether abnormal cells are
present. It may take several days to receive results from a sputum
cytology.
Sputum cytology| Normal: | Normal lung cells are present in the sputum
sample. |
|---|
| Abnormal: | Abnormal cells are present in the sputum
sample. Abnormal cells may mean lung conditions such as
pneumonia, inflammation, the buildup of asbestos
fibers in the lungs (asbestosis), or
lung cancer. |
|---|
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include a sample that is
too small; is dried out; contains only saliva; or is from nasal secretions, not
your airway.
What To Think About
- There is a chance of
false-negative test results with sputum cytology. This
means that the test shows a lung condition is not present when it actually
is present. Follow-up testing may need to be done if your symptoms
continue.
- A sputum culture is a test to find and
identify bacteria or fungi that are infecting the lungs or breathing passages.
It is also done to identify the best antibiotic to treat a lung infection. To learn more, see the topic
Sputum Culture.
- Bronchoscopy or
a needle lung
biopsy are more commonly used than sputum cytology
because the results provide more information about airway problems.
References
Other Works Consulted
- Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
- Fischbach F, Dunning MB III (2015). A Manual of Laboratory and Diagnostic Tests, 9th ed. Philadelphia: Wolters Kluwer Health.
- Pagana KD, Pagana TJ (2014). Mosby's Manual of Diagnostic and Laboratory Tests, 5th ed. St. Louis: Mosby.
Credits
ByHealthwise Staff
Primary Medical ReviewerAdam Husney, MD - Family Medicine
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerElizabeth T. Russo, MD - Internal Medicine
Current as ofJune 2, 2017