PCR for Detection of Bacteremia

This letter refers to the article by Heininger et al. (1). In the introduction section, the authors mention that bacteremia is diagnosed in only approximately 4 to 12% of all blood cultures inoculated in patients with sepsis.

Generally, the denominator for calculating the rate of positivity in blood cultures is the number of blood cultures processed by the laboratory. However, one should keep in mind that blood cultures are inoculated not only to confirm the clinical diagnosis of sepsis but also to rule out sepsis in other clinical situations, such as patients with fever and clinical diagnosis of lymphoma, patients with malaria returning from a tropical country where typhoid fever needs to be ruled out, etc. If the denominator for calculating the rate of positive blood cultures is the number of patients with the clinical diagnosis of sepsis, then up to 63% of blood cultures yield a pathogen of clinical significance, as we have shown in a prospective study (2).