>1,100 (prosthetic joint)
>25,000; LR=2.9
>50,000; LR=7.7
>100,000; LR=28
>64% (prosthetic joint)
>90%
Viscosity of synovial fluid may actually be decreased in inflammatory or infectious etiologies, as hyaluronic acid concentrations decrease
The presence of crystals does not rule out septic arthritis; however, the diagnosis is highly unlikely with synovial WBC < 50,000
Arthrocentesis: knee
Arthrocentesis: elbow
Arthrocentesis: ankle
Arthrocentesis: shoulder
Arthrocentesis: hip
Arthrocentesis: wrist
Arthrocentesis: finger
Arthrocentesis: toe