Introduction: Procalcitonin (PCT) offers better specificity than C-reactive protein (CRP) to detect SBI. However, their cost limited their use and routine application. The objective of this work is to determine the cost-effectiveness of PCT against CPR or Rochester scale in infants between 1 and 3 months from the perspective of the third payer in Colombia.

Methods: A Monte Carlo simulation was performed with a hypothetical cohort of 10,000 patients with fever without focus (FWS) between 1 to 3 months, to estimate the number of cases correctly diagnosed for each test and the associated costs with each test.

Results: The test with the highest number of correctly diagnosed cases was PCT 79%, followed by C-reactive protein 75%, and the Rochester scale 68%. The test with the lowest cost per patient was PCT $645 (95% CI US$646-US$645) followed by C-reactive protein U$ 653 (95% CI US$655-$645) and Rochester scale US$804 (95% CI US$807-US$804). This position of dominance of PCT eliminated the need to calculate an incremental cost effectiveness ratio.

Conclusions: PCT is the most cost-effective strategy for the detection of IBS in infants with FWS. These results should be interpreted within the clinical context of the patient and not as a single method for therapeutic decision-making.

Keywords: Bacterial Infections; Child; Colombia.