Healthcare associated infection (HAI) rates are subject to public reporting, and are linked to hospital reimbursement from the Centers for Medicare and Medicaid Services (CMS). The increasing pressure to lower HAI rates comes at a time when advances in the clinical microbiology laboratory (CML) provide more precise and sensitive tests, altering HAI detection in ways that may increase reported HAI rates. I review how changing CML practices can impact HAI rates, and how the financial implications of HAI metrics may produce pressure to change diagnostic testing practices. Finally, I provide suggestions for how to respond to this rapidly changing environment. SCENARIO 1: During an investigation of rising rates of central-line associated bloodstream infection (CLABSI), the infection prevention program (IPP) notes that some CLABSIs were due to organisms that grew in only one of several blood cultures, and which prior to the institution of matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) for organism identification would have been classified as contaminants. An example included a CLABSI attributed to an unusual species of Actinomyces that previously would have been categorized as a "diphtheroid". Your hospital leadership requests that you either revert to former identification methods or change your reporting in a way that prevents these events from being classified as CLABSIs. SCENARIO 2: Since you changed to a nucleic acid amplification test (NAAT) for Clostridium difficile detection, your positivity rate has increased by over 100%. The rate of hospital-onset C. difficile infection (HO-CDI) has increased similarly. During an investigation of the increase in CDI, you find that many samples positive by NAAT are toxin negative by enzyme immunoassay (EIA), and that many patients with low pretest probability of disease are being tested. However, after an initiative to improve testing practices, your hospital-onset CDI Lab ID-event rate remains high (standardized infection ratio (SIR) >1). Concerned about how this rate will impact the value-based purchasing (VBP) and healthcare-associated condition (HAC) scores, your hospital leadership asks you to consider a change back to EIA for CDI diagnosis. SCENARIO 3: Even after a campaign to reduce your hospital's rate of catheter-associated urinary tract infection (CAUTI) through a reduction in catheter use and improvement in catheter placement and care, the CAUTI rate remains unacceptably high. Your hospital epidemiologist sets up a meeting with you, to discuss how to reduce the number of urine cultures ordered or performed by the laboratory, as another way to reduce both the CAUTI rate and unnecessary antibiotic use. She is open to almost any idea to reduce culture ordering, from using "reflex testing" (culture only performed when urinalysis reveals evidence for inflammation) to requiring laboratory director approval for every urine culture ordered from catheterized inpatients.
Journal of clinical microbiology. 2017 Jan 25 [Epub ahead of print]
Daniel J Diekema
Departments of Internal Medicine and Pathology, University of Iowa Carver College of Medicine, Iowa City, IA .