synovial fluid analysis

synovial fluid analysis

Lab medicine The evaluation of SF obtained by aspiration from the knee, shoulder, hip, elbow, less commonly from another joint; SFA is commonly performed on younger Pts to detect infection–eg,
with staphylococcus or TB and in older Pts to categorize type of inflammation–eg, rheumatoid arthritis, pseudogout, exclude gout

Synovial fluid analysis*

Type   Appearance  Glucose^‡  WBC/mL PMNs Viscosity  

Normal Clear yellow < 10 mg/dL < 200/µL < 25% ↑

Noninflammatory  Clear yellow < 10 mg/dL < 2000/µL < 25% ↑

Inflammatory  Slightly turbid < 20 mg/dL <5000/µL < 50% ↓

Septic-mild Turbid < 40 mg/dL <50,000/µL  50-90% ↓

Septic-severe Turbid/purulent> 20 mg/dL >50,000/µL > 90% ↓

*after JB Henry, Ed, Clinical Diagnosis & Management by Laboratory Methods, 18^th edition, WB Saunders, 1991

‡Synovial fluid and blood difference