What Is a Joint Fluid Culture?
A culture of your joint fluid is a laboratory test. It identifies
organisms that can cause infection in your joint fluid. The actual culture test
takes place in a laboratory. The joint fluid is also used to test for the
presence of protein, glucose, or crystals. For example, the presence of
monosodium urate monohydrate crystals indicates you may have gout. The culture
can also determine the number of white and red blood cells in the fluid.
You may experience pain and discomfort in your joints due to:
- a sprain
- a sports injury
- repetitive movements
- inflammatory arthritis caused by an immune
If you have chronic pain or inflammation in the joints without an
apparent cause, your doctor may order a joint fluid culture to help diagnose a
variety of conditions, including several forms of arthritis, gout, and joint
How Do I Prepare for a Joint Fluid Culture?
Before you have a joint fluid culture, tell your doctor if you’re
taking any prescription drugs or over-the-counter medications or supplements.
Also, tell your doctor if you’re pregnant or have a history of bleeding
disorders. You may need to fast before the procedure, but there’s no other
preparation required. Ask your doctor for specific instructions based on your
What Happens During a Joint Aspiration?
Your doctor will get a sample of your joint fluid by performing a
joint aspiration. A joint aspiration procedure can occur:
- during a hospital stay
- on an outpatient basis in a hospital
- at the doctor’s office
As preparation for the removal of joint fluid, you’ll remove your
clothing and put on a hospital gown. Your doctor will clean the site of the
aspiration. The entire procedure occurs under sterile conditions. The doctor
may do a joint aspiration using a local anesthetic near the site of the needle insertion.
Joint aspiration is usually performed on the knee, but it may also be performed
Your doctor will remove fluid from your joint using a needle and
syringe in a procedure called a joint aspiration. You’ll feel a needlestick and
possibly a slight stinging sensation. The doctor will draw a small sample of
fluid into the syringe. Then, they’ll remove the needle and apply a bandage
over the injection site.
Joint aspiration can also relieve pressure due to fluid
collecting around the joint. Conditions like bursitis can cause liquid to
collect around a joint. In some cases, a doctor will inject medication into the
joint after removing the fluid if they’re certain that an infection doesn’t
exist. Usually, this medication will be a corticosteroid, which is a medication
that reduces inflammation. This is effective in treating bursitis and
tendonitis. However, the relief is often temporary. The Cleveland
Clinic notes that it’s common for fluid to collect around the joint again.
After collecting the sample, your doctor will send it to a
laboratory for testing. The lab will test the fluid sample for:
- blood cells
- organisms, such as bacteria, fungi, and viruses
What Happens After a Joint Aspiration?
You’ll be able to go home shortly after the procedure. Keep the
aspiration site clean and dry. Remove the bandage as advised by your doctor. Aspirin
may cause bleeding after the procedure. You should ask your doctor which pain
relievers you should take. Because your joint may swell again, your doctor may
recommend that you elevate the extremity and apply an ice bag to your joint.
What Are the Complications Associated with
Doctors consider joint aspiration to be a safe procedure. It’s
normal for your joint to feel sore, uncomfortable, or appear bruised for a few
days. However, contact your doctor immediately if you experience:
- a fever
- discharge from the aspiration site
- an increasing amount of pain at the aspiration
- a restricted range of motion in the joint
These symptoms could be signs of infection and need quick
What Do the Results Mean?
The laboratory will send a report to your doctor. Your doctor
will then review it with you. If the lab found abnormalities, you may need
other tests to narrow down the cause and assess treatment options. Pain and
swelling of your joint may be due to a variety of conditions other than injury,
gout, or inflammatory arthritis. Some of the other possible causes include:
- bacterial arthritis
- fungal arthritis
- gonococcal arthritis
- tuberculosis arthritis
Your doctor will recommend treatments based on the specific
results of your test.