MRSA Tests
Reviewed
Also called: MRSA screening, methicillin-resistant Staphylococcus aureus screening, methicillin-resistant Staphylococcus aureus culture
A MRSA test looks for methicillin-resistant Staphylococcus aureus bacteria in a sample of fluid or tissue. The sample is often taken from your nose or a wound. MRSA is a type of staph bacteria that is resistant to many common antibiotics.
Specimen: Wound, nose, blood, or urine sample
Why this test may be ordered
- To find out if you have a MRSA infection.
- To see if treatment for a MRSA infection is working.
Preparation and collection
No special preparations are needed.
A health care provider collects a sample. Steps may include: wound sample (using a swab from the site of your wound), nasal swab (using a special swab from your nose), blood test (from a vein in your arm), or urine test (you provide a sterile sample in a cup).
Wound sample: You may feel a little pain when the sample is taken. Nasal swab: May be slightly uncomfortable. Blood test: Slight pain or bruising at the needle site. Urine test: No known risks. These effects are usually mild and temporary.
Understanding results
Your healthcare provider will interpret your results based on your symptoms, medical history, and other test results. There is no single reference range for this test.
- Positive: MRSA bacteria were detected in your sample. Limitation: A positive result means you have a MRSA infection. However, the bacteria can also be present without causing infection (colonization). Your provider will determine the clinical significance based on your symptoms and history. Next step: Treatment will depend on how serious the infection is. For mild skin infections, your provider may clean, drain, and cover the wound and may prescribe antibiotics. For more serious cases, you may need to go to the hospital and get treated with powerful antibiotics through an IV.
- Negative: No MRSA bacteria were found in your sample. Limitation: A negative result suggests you likely do not have a MRSA infection at the site tested. However, a negative result does not rule out MRSA colonization elsewhere or a later infection. Next step: If you have symptoms but a negative result, your provider may repeat the test or consider other causes.
- The test detects MRSA bacteria but does not distinguish between colonization (carrying the bacteria without infection) and active infection. Your healthcare provider will consider your symptoms and medical history to interpret the result.
- Culture results typically take 24–48 hours because bacteria need time to grow. A molecular test (on nasal swabs) can give results in as little as 5 hours.
What to do next
If your result is positive, your provider will determine treatment based on the severity of the infection. For mild skin infections, they may clean, drain, and cover the wound and may prescribe antibiotics. For serious infections, you may need hospital treatment with IV antibiotics. Always follow your provider's instructions and complete your full course of antibiotics.
- This test is a laboratory test, not a questionnaire or screening assessment.
- This test is a laboratory test, not a non-diagnostic screening assessment. It is used to detect MRSA bacteria and can help diagnose an infection or monitor treatment.
- This test is a laboratory test, not an imaging procedure.
- This test is a laboratory test, not a confirmatory test for a specific genetic condition.
- This test is a laboratory test, not a procedure.