Infectious Diseases Laboratory Stewardship

Laboratory stewardship is increasingly recognized as a critical component of health care. Although the subspecialty of infectious diseases (ID) has been treatment oriented for many years, the advent of many new and sophisticated tests supplicates us to turn our attention to potential improper use of the clinical laboratory, which can contribute to unnecessary antimicrobial treatment and an array of downstream negative effects associated with such practice. An estimated 70% of downstream medical decisions are based on the results of pathology and laboratory tests. ID diagnostic stewardship aims to optimize patient care and improve outcomes by utilizing the results of laboratory tests to guide clinical interventions and therapeutics. Evidence-based guidelines advocate for the use of clinical decision tools such as the Centor-McIsaac criteria to help determine the need for group A beta-hemolytic Streptococcus (GAS) testing on patients presenting with suspected pharyngitis. Having observed an undue number of nucleic acid assay tests (NAATs) performed in our emergency department on adults for seemingly unjustified indications, we elected to conduct a retrospective records review study intended to quantitate such occurrences and to gain a better understanding if and how the results of this laboratory test ultimately effected clinical decision making, ultimately to improve our hospital's laboratory utilization. Of 167 patients tested for GAS, 164 (98%) had a calculated Centor-McIssac criteria score of −0 to 1, indicating a 1% to 2.5% probability of GAS pharyngitis suggesting no need for microbiologic laboratory testing or antimicrobial treatment, inferring poor pretest evaluation and suboptimal laboratory utilization.