Explanation:
The original Kocher criteria (published in 1999) consist of four predictive factors for pediatric septic arthritis of the hip: non-weight-bearing on the affected side, ESR > 40 mm/hr, fever > 38.5°C (101.3°F), and a serum WBC count > 12,000 cells/mm³. If all four criteria are present, the predicted probability of septic arthritis is 99%. CRP > 2.0 mg/dL was later added in modified versions of the criteria but was not one of the original four. Reference: Tachdjian's Pediatric Orthopaedics, 6th Edition.