Culture - joint fluid

Joint fluid culture is a laboratory test to detect infection-causing organisms in a sample of fluid surrounding a joint.

A sample of joint fluid is needed. This may be done in a doctor's office using a needle, or during an operating room procedure. For more information on this procedure, see: Joint fluid aspiration.

The fluid sample is sent to a laboratory where it is placed on a special dish and watched to see if bacteria, fungus, or viruses grow. This is called a culture.

If such microorganisms are detected, other tests may be done to further identify the infection-causing substance and determine the best treatment.

There is no special preparation needed for the lab culture. For information on preparing for the removal of joint fluid, see: Joint fluid aspiration.

The joint fluid culture is done in a laboratory and does not involve the patient.

For information how the procedure to remove joint fluid feels, see: Joint fluid aspiration.

Your doctor may order this test if you have unexplained pain and inflammation of a joint or a suspected joint infection.

The test result is considered normal if no organisms (bacteria, fungi, viruses) grow in the laboratory dish.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Abnormal results are a sign of infection in the joint. Infections may include:

• Fungal arthritis
• Gonococcal arthritis
• Non-gonococcal (septic) bacterial arthritis

There are no risks to the patient associated with a lab culture. For risks related to the removal of joint fluid, see: Joint fluid aspiration.