What is the procedure code for a diagnostic needle arthrocentesis performed on left side of knee and fluid was evaluated?

The procedure code for a diagnostic needle arthrocentesis (joint aspiration) performed on the left knee is typically 20610. This code is used for aspiration and/or injection into a major joint or bursa, specifically indicating the left side when documenting. It is important to ensure that the documentation reflects the evaluation of the fluid for accurate coding and billing.