Do we need this blood culture?

OBJECTIVES This study describes blood culture collection rates, results, and microbiology laboratory charges for 4 leading pediatric inpatient diagnoses (asthma, bronchiolitis, pneumonia, and skin and soft tissue infection [SSTI]) in low-risk patients. METHODS This retrospective cohort study was conducted at an urban, academic, quaternary children's hospital. The study period was from January 1, 2011, to December 31, 2011. Inclusion criteria were as follows: 6 months to 18 years of age and primary diagnosis of asthma (International Classification of Diseases, Ninth Revision [ICD-9] codes 493.91-493.92), bronchiolitis (ICD-9 codes 466.11 and 466.19), SSTI (ICD-9 codes 680.00-686.99), or pneumonia (community-acquired pneumonia; ICD-9 codes 481.00-486.00). Patients with complex chronic conditions were excluded. Data were collected via administrative billing data and chart review. Descriptive statistics were performed; χ(2) tests were used for categorical variables, and nonparametric tests were used for continuous variables because of non-normal distributions. RESULTS Administrative data review included 5159 encounters, with 1629 (32%) inpatient encounters and 3530 (68%) emergency department/outpatient encounters. Twenty-one percent (n = 343) of inpatient encounters had blood cultures performed, whereas 3% (n = 111) of emergency department/outpatient encounters had blood culture testing performed. Inpatient blood culture utilization varied according to diagnosis: asthma, 4%; bronchiolitis, 15%; pneumonia, 36%; and SSTI, 46%. Charts were reviewed for all 343 inpatients with blood culture testing. Results of all the blood cultures obtained for asthma and bronchiolitis admissions were negative, with 98% and 99% negative or false-positive (contaminant) for SSTI and community-acquired pneumonia, respectively. The approximate financial impact of blood culture utilization (according to gross microbiology laboratory charges) approximated $100 000 over the year for all 4 diagnoses. CONCLUSIONS There was a high rate of negative or false-positive blood culture results for these common inpatient diagnoses. In addition, there was a low rate of clinically significant true-positive (pathogenic) culture results. These results identify points of potential blood culture overutilization.