Unnecessary blood tests and imaging common in cellulitis hospitalizations, study finds

Over two-thirds of patients with uncomplicated cellulitis received imaging, none of which would have been recommended by guidelines from the Infectious Diseases Society of America.

The majority of patients with uncomplicated cellulitis seen in an ED received more testing than recommended by guidelines, a recent single-center study found.

To evaluate the appropriateness of tests and imaging for cellulitis, the retrospective cohort study included 183 patients treated in the Massachusetts General Hospital ED between October 2014 and February 2017. All had a presumed diagnosis of uncomplicated cellulitis and were subsequently admitted to either an inpatient medicine or ED observation unit. Results were published as a research letter on April 2 by JAMA Internal Medicine.

Almost a third (32.8%) of the patients received blood cultures, but growth was detected in only one case. Guidelines from the Infectious Diseases Society of America (IDSA) would have called for cultures based on history and vital signs in only 18 patients (10%). Over two-thirds of the patients (67.8%) received imaging. None of those patients were febrile or neutropenic, so all of the imaging was contraindicated by IDSA guidelines. While most patients received no or one form of imaging, 30 (16.4%) underwent two forms, nine (4.9%) underwent three forms, and two (1.1%) underwent four imaging modalities. Ultrasonography was the most common form (46.0%), followed by radiography (29.0%), CT (16.0%), and MRI (6.0%).

The results of imaging changed diagnosis and management in only eight patients: one with hematoma, five with abscesses, and two with osteomyelitis. The researchers looked for patient factors that predicted the use of imaging and found that higher rates of lymphedema and higher serum glucose levels were the only factors that differentiated the patients who received imaging from those who didn't.

The authors gathered data on costs of blood tests and imaging, as well as national rates of hospitalization for cellulitis, to extrapolate the costs of this non-guideline-concordant care. Finding that “the cost of these largely clinically useless diagnostic studies is approximately $226.9 million dollars annually,” they recommended that “imaging and blood cultures should be pursued only in patients who are severely immunocompromised or experiencing systemic toxic effects.”