CALCA and infection: Procalcitonin has been demonstrated to be a valuable biomarker for distinguishing between infection and systemic inflammatory response.7, 8, 9 Several studies have shown PCT to be a promising biomarker for diagnosing postoperative infection in pediatric patients undergoing open-heart surgery with CPB.10, 11, 12, 13, 14, 15, 16 However, some studies have reported indefinite results regarding the diagnostic role of PCT tests in postoperative infection in pediatric patients undergoing open cardiac surgery with CPB.14