quality:correction, structural:summarization, stylistic:style_transfer, structural:expansion
Joint aspiration

In the joint fluid, the typical white blood cell count in septic arthritis is over 50,000–100,000 cells per 10 −6 /l (50,000–100,000 cell/ mm 3); where more than 90% are neutrophils is suggestive of septic arthritis. For those with prosthetic joints, white cell count more than 1,100 per mm 3 with neutrophil count greater than 64% is suggestive of septic arthritis. However, septic synovial fluid can have white blood cell counts as low as a few thousand in the early stages. Therefore, differentiation of septic arthritis from other causes is not always possible based on cell counts alone. Synovial fluid PCR analysis is useful in finding less common organisms such as Borrelia species. However, measuring protein and glucose levels in joint fluid is not useful for diagnosis.