Bacteriasnvcult
A laboratory test that identifies bacteria in the fluid surrounding joints to diagnose joint infections.
{"This test detects bacterial infections in joint fluid","It helps diagnose septic arthritis, a serious joint infection","Results guide antibiotic treatment selection","Sample is collected via joint aspiration (arthrocentesis)","Early diagnosis prevents joint damage"}
Key facts at a glance
- LOINC
- 621-3
- Short code
- SFBC
- Synonyms
- Bacteria Snv Cult
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile, leak-proof container (e.g., sterile screw-cap tube or sterile cup); anaerobic transport vial recommended for anaerobic culture; blood culture bottles may be used for small volumes.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- culture
- CPT
- 87075
- SNOMED
- 42810006
- Specimen volume
- 1-5 mL of synovial fluid recommended; minimum 0.5 mL acceptable; send as much fluid as possible to optimize culture yield.
- Stability
- Room temperature: deliver to laboratory within 1-2 hours of collection for optimal recovery. If delayed, refrigerate at 2-8°C for up to 24 hours. Do not freeze. Specimens for anaerobic culture should be maintained at room temperature.
- Hemolysis max
- 300
- TAT
- 48–336 hours
- Order
- routine
What is this test?
The Synovial Fluid Culture test analyzes the fluid from your joint to identify any bacteria that may be causing an infection. Synovial fluid is the viscous liquid that cushions and lubricates the joints, allowing smooth movement. When bacteria enter this fluid, they can cause a serious condition called septic arthritis.
How is the sample collected?
A healthcare provider will insert a thin needle into your joint to withdraw a small amount of synovial fluid. This procedure is called arthrocentesis or joint aspiration. The area will be cleaned and numbed to minimize discomfort. The collected fluid is then sent to a laboratory for bacterial culture and identification.
What happens in the laboratory?
In the lab, the synovial fluid is placed in special culture containers that allow bacteria to grow. Technicians monitor the sample over several days to see if bacteria multiply. If bacteria grow, they are identified using various methods, and antibiotic sensitivity testing determines which antibiotics can effectively treat the infection.
Why is this test performed?
Your doctor may order this test if you have symptoms of a joint infection, such as severe joint pain, swelling, warmth, redness, or fever. It is crucial for diagnosing septic arthritis, which requires prompt treatment to prevent permanent joint damage. The test is also used to monitor treatment effectiveness.
What do the results mean?
A negative result means no bacteria were detected in the culture. However, false negatives can occur if you have already started antibiotics. A positive result identifies the specific bacteria causing the infection and which antibiotics will be most effective. Your doctor will use these results to prescribe the most appropriate treatment.
Reference range
No growth of pathogenic bacteria. Identification reported qualitatively (e.g., Staphylococcus aureus, Streptococcus pyogenes, Kingella kingae, Brucella species, Neisseria gonorrhoeae, Mycobacterium species when appropriate).N/A
Arthrocentesis should be performed under strict aseptic technique by a qualified healthcare provider. Skin overlying the joint should be disinfected with chlorhexidine or povidone-iodine. If possible, antibiotics should be withheld prior to specimen collection unless the patient is critically ill.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is the joint aspiration procedure painful?
How long does it take to get results?
Do I need to prepare for this test?
What happens if I have a joint infection?
Can the test detect non-bacterial joint problems?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy