Good reminder (for some this may be new!) on overuse of an important test. Thanks to Journalwatch for this read.
Daniel J. Pallin, MD, MPH Reviewing Torres J et al., Am J Emerg Med 2017 May 26;
Even with selection bias and inclusion of injection drug users, this single-center study found that only 7% of blood cultures in admitted patients were positive.
Blood cultures are positive in about 4% of all comers with cellulitis. In a prospective, observational, single-center study, researchers assessed the rate of positive blood cultures in admitted patients with skin and soft tissue infections, and in the subsets with injection drug use or fever. Importantly, the investigators did not determine who would undergo blood cultures.
Of 246 admitted patients with skin infection, 86 (35%) had blood cultures, and 7.0% of cultures were positive. Among the 29 blood-cultured patients who were febrile, 3.5% had positive blood cultures. Of 101 admitted patients who were injection drug users, 46% had blood cultures, and of these, 8.7% were positive.