joint effusion (knee effusion)

Laboratory

• joint aspiration for synovial fluid analysis
  • synovial fluid cell count
  • gram stain
  • synovial fluid culture
• blood cultures* if febrile
• systemic inflammatory markers may be elevated
  • erythrocyte sedimentation rate (ESR)
  • serum C-reactive protein (serum CRP)

* special recommendations for prosthetic joints (see infected prosthesis)

More general terms

• effusion

Additional terms

• joint aspiration (arthrocentesis)