Introduction: procalcitonin (PCT) is a marker whose utility for the diagnosis of bacterial infections has been demonstrated. Since some types of surgery (for example heart surgery) induce PCT liberation, further studies are needed in order to assess its utility in those circumstances. Objective: to assess the ability of PCT (with a cut point of PCT > 2 ng/ml) to discriminate between systemic inflammatory response syndrome (SIRS) with sepsis and without sepsis during the early post-operative period. Methods: 119 patients who developed SIRS during the first 72 hours after surgery were assessed. Measurements of semiquantitative serum PCT were performed, and follow-up up the patients’ clinical evolution was carried out in order to classify their condition as septic SIRS or non-septic SIRS, according with the sepsis protocol of the Cardio-Infantil Foundation. Results: the sensitivity and specificity of PCT for diagnosing sepsis in the postoperative setting Niveles sericos de procalcitonina y sepsis en el posoperatorio inmediato de diversos tipos de cirugia Serum procalcitonin levels and sepsis during the immediate postoperative period in several types of surgery EDUARDO ZUNIGA, RENE ESCOBAR. ALVARO ARANGO, JUAN MAURICIO PARDO, ANGELA FERNANDA ESPINOSA, LUZ EFIGENIA BERNAL • BOGOTA D.C. Dr. Eduardo Zuniga Rodriguez: Medico Internista, Universidad del Rosario; Dr. Rene Escobar: Medico Internista, Universidad del Rosario; Dr. Alvaro Arango: Infectologo; Dr. Juan Mauricio Pardo: Medico Internista, Universidad del Rosario; Dra. Angela Fernanda Espinosa: Epidemiologa, Universidad del Rosario; Dra. Luz Efigenia Bernal: Bacteriologa. Institucion: Fundacion Cardio-Infantil Instituto de Cardiologia. Bogota, D.C. Correspondencia. Dr. Eduardo Zuniga Rodriguez, Calle 163 a No 13 B-60, Telefono: 6672727 ext 4500, Bogota, D.C. E-mail: eduardo.zuniga93@urosario. edu.co Recibido: 17/VII/08 Aceptado: 30/I/09