Sputum stain for mycobacteria
Sputum stain for mycobacteria is a test to check for a type of bacteria that cause tuberculosis and other kinds of infection.
Acid fast bacilli stain; AFB stain; Tuberculosis smear; TB smear
How the test is performed
To obtain a sputum sample, you will be asked to cough deeply and spit the substance that comes up from the lungs (sputum) into a container. You may be asked to inhale a mist of salty steam in order to cough more deeply and produce sputum. If you still don't produce enough sputum, you might have a bronchoscopy.
The specimen is spread on a microscope slide. The cells of the specimen are stained with dyes and then examined under the microscope.
If the stain shows mycobacteria, the specimen may be placed in culture media, which encourages them to grow. (Specimens are often cultured even if no mycobacteria are seen, because sometimes the number of organisms is so low that they don't show up with staining, but they eventually grow on the culture medium.)
How to prepare for the test
It can help to drink a lot of fluids the night before the test. It makes the test more accurate if it's done first thing in the morning.
How the test will feel
There is no discomfort, unless a bronchoscopy needs to be performed.
Why the test is performed
The test is performed when the doctor suspects tuberculosis or other Mycobacterium infection.
Results are normal when no mycobacterial organisms are found.
What abnormal results mean
Abnormal results show that the stain is positive for:
- Mycobacterium tuberculosis
- Mycobacterium avium-intracellular
- Other mycobacteria or acid-fast bacteria
What the risks are
There are no risks, unless bronchoscopy is performed.
To increase the accuracy of this test, it is sometimes done three times, often three days in a row.
There are more sophisticated tests that are sometimes used to stain sputum for mycobacteria. Check with your health care provider to see if these are available in the laboratory.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. ©1997-2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
Sign Up for Free Newsletters
Ask Your Doctor the RIGHT Questions!
the most from your doctor visit.
Emailed right to you!
The Ask Your Doctor email series
may contain sponsored content.
18+, US residents only please.
Explore Original Articles About...
Get the MOST from QualityHealth
- Top Searches
- 1. Arthritis Management: Nature Heals
- 2. 5 Digestive To-Dos
- 3. Men: Should You Shave It or Leave It?
- 4. Today's Top Fitness Trends
- 5. Sugar and Osteoarthritis : The Link
- 6. Can't Afford Your Hospital Bills?
- 7. Stay Energized All Day Long
- 8. Phobias: Who Has Them and Why?
- 9. What If Your EpiPen Fails?
- 10. 5 Costly Medical Billing Mistakes
- 1. Ice Falls Can Cause Serious Injuries
- 2. Can Inactivity Act Like a Disease?
- 3. Kale Snack Recipe for Diabetics
- 4. How Running Affects Arthritis
- 5. Sugar and Your Immunity System
- 6. Do Weight Loss Supplements Work?
- 7. 5 Super Foods for Spring
- 8. The Hazards of Reusable Bags
- 9. How to Avoid Ingrown Hairs
- 10. Health Tip: Constantly Change Shoes
- 1. 4 Common Treatments for Epilepsy
- 2. What Does a Urogynecologist Do?
- 3. GERD Without Heartburn? It's Possible
- 4. Graston Technique: Can It Work on You?
- 5. Music Therapy Can Help Autism
- 6. 8 Ways to Fight MS-Related Fatigue
- 7. Can You Still Bleed After Menopause?
- 8. Be Your Own Health Care Advocate
- 9. Why Is Syphillis on the Rise?
- 10. Ideal Weight vs. Happy Weight
The material on the QualityHealth Web site is for informational purposes only, and is not a substitute for medical advice, diagnosis, or treatment provided by a physician or other qualified health provider. See additional information.