To assess the cost-effectiveness of blood cultures for patients with cellul
itis, a retrospective review was conducted of clinical and microbiological
data for all 757 patients admitted to a medical center because of community
-acquired cellulitis during a 41-month period. Blood cultures were performe
d for 553 patients (73%); there were a total of 710 blood samples (i.e., a
mean of 1.3 cultures were performed per patient). In only 11 cases (2.0%) w
as a significant patient-specific microbial strain isolated, mainly beta-he
molytic streptococci (8 patients [73%]), An organism that was considered a
contaminant was isolated from an additional 20 culture bottles (3.6%). The
cost of laboratory workup of the 710 culture sets was $36,050. Isolation of
streptococci led to a change from empirical treatment with cefazolin to pe
nicillin therapy for 8 patients. All patients recovered. In conclusion, the
yield of blood cultures is very low, has a marginal impact on clinical man
agement, and does not appear to be cost-effective for most patients with ce
llulitis.