I. Technique

  1. Wright's Stain for cell count with differential

II. Normal Synovial Fluid

  1. Less than 200 White Blood Cells (WBC) per mm3
  2. Polymorphonuclear Leukocytes (PMN) less than <50%

III. Non-Inflammatory fluid: 200 - 2000 WBC/mm3

IV. Inflammatory fluid: 2000 - 50,000 WBC/mm3 (mild < 20,000)

V. Septic fluid: Over 50,000 WBC/mm3 (especially >100,000)

  1. Septic Arthritis until proven otherwise

VI. Reference

  1. Kolba (1984) Prim Care 11:211-8

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