Which of the following is not a component of Kocher's criteria when diagnosing septic arthritis of the hip?

Ans. D. C-reactive protein (CRP) >20.Due to the rapid chondro lytic effect of pus within the joint, pyogenic septic arthritis of the hip in children represents a surgical emergency. It can be difficult to distinguish a septic hip from other causes of hip pain in children. In such cases, whilst clinical suspicion remains of paramount importance, Kocher's diagnostic algorithm is a useful tool. The four diagnostic criteria are non-weight-bearing, ESR >40, WBC >12 and fever. The predicted risk of a septic arthritis varies with the number of positive criteria. The algorithm has been tested retrospectively and prospectively. In the prospective validation study the probabilities were lower:Number of criteria metChance of septic arthritis (original study)Chance of septic arthritis (validation study)13%9.5%240%35%393%73%499.6%93%