Final answer:
In septic arthritis, the white blood cell (WBC) count in the synovial fluid obtained through arthrocentesis is used to assess the severity of the infection. WBC counts above 50,000 cells/mm³ are indicative of septic arthritis.
Step-by-step explanation:
In septic arthritis, arthrocentesis is performed to determine the presence of infection. The white blood cell (WBC) count in the synovial fluid obtained through arthrocentesis is used to assess the severity of the infection. WBC counts above 50,000 cells/mm³ are indicative of septic arthritis, while counts below 25,000 cells/mm³ are more commonly associated with other joint diseases.