Findings on Analysis of Synovial Fluid

Findings on Analysis of Synovial Fluid

Classification of effusion	Features	White cell count	Causes
Normal synovial fluid	Clear colourless, viscus	<200/mm³ <25% polymorphs
Non-inflammatory	Cloudy, yellow, viscus	200–2000/mm³ <25% polymorphs	Common: Osteoarthritis Trauma Uncommon: Early or subsiding inflammation, Osteochrondritis dissecans Neuropathic arthropathy, Pigmented villonodular synovitis
Inflammatory	Cloudy, yellow, watery	2000–100,000/mm³ >50% polymorphs	Common: Rheumatoid arthritis Crystal arthropathies Psoriatic arthritis Uncommon: Reiter syndrome Ankylosing spondylitis Arthritis associated with inflammatory bowel disease Rheumatic fever Systemic lupus erythematosus Hypertrophic osteoarthropathy Scleroderma
Septic	Purulent	>80,000/mm³ >75% polymorphs	Common: Bacterial Mycobacterial Uncommon: Fungal