My Doctor says she cannot pull the Synovial Fluid out as it is "Extremely Less". Does this make any sense?

Question

I had Gonococcal Arthritis and the disease is gone however its been 9 months since, and its left my knees mildly swollen or inflamed. I told the Doc to pull my synovial fluid out and check it for infection, but she says that She cannot pull the Synovial Fluid out as it is "Extremely Less".

I mean Does this make any sense? I mean can this medically happen?