As an alternative to the original Kocher criteria, Baldwin et al. found that by increasing the number of criteria they achieved higher predictive values which included: pain with an arc of motion below 30 degrees, CRP level >4.0 mg/L, notion of episodes of fever, and an age below 2 years were all positive predictive values which were able to help distinguish septic arthritis of the knee from non-septic forms such as Lyme arthritis [27]. The gene discussed is CRP; the disease is bacterial arthritis.