C. diff Testing
Reviewed
C. diff testing checks a stool sample for signs of infection with Clostridioides difficile bacteria. The bacteria can release toxins that irritate the colon and cause diarrhea, abdominal pain, nausea, loss of appetite, and fever. Most infections occur while taking certain antibiotics or within weeks after finishing them. Testing is especially important if you have symptoms and are at high risk (e.g., recent antibiotic use, age 65 or older, recent hospital or nursing home stay, weakened immune system, or prior C. diff infection).
Preparation and collection
No special preparation is needed.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- A negative result on a C. diff toxin test alone is not enough to rule out a C. diff infection because toxins can break down quickly if the sample is not kept cool.
- A GDH antigen test can show if C. diff is in your body, but it cannot tell if it is making you sick.
- After treatment for a C. diff infection, you will not be tested again to see if you are cured because it is common to still have C. diff in your body after you get better. A test would only show that the bacteria is still there, not whether you are likely to get sick again.
What to do next
If you have questions about your results and/or treatment, talk with your provider. To lower your chance of getting or spreading C. diff: avoid taking antibiotics you do not really need; let all your providers know if you have had a C. diff infection (including your dentist); wash your hands with soap and water every time you use the bathroom and before you eat anything. C. diff is contagious—people who have it spread it by not washing their hands before touching people and things that other people touch.