False positive blood cultures are responsible for significant avoidable direct and indirect costs to the healthcare system. There are a number of material cost drivers associated with patients that are inaccurately diagnosed with septecemia based on contaminated blood cultures:
- Increased pharmacy, laboratory, radiology/diagnostic imaging costs
- Extended inpatient length of stay
- Additional costs associated with complications resulting from extra, unnecessary time in hospital
The financial impacts of false positives are twofold: increased costs associated with unnecessary patient treatment and decreased bed availability which can translate to revenue opportunity cost for hospitals that are consistently full.
In 2008, Gander et al conducted a study at Parkland Hospital in Dallas which quantified incremental charges per false positive blood culture patient-instance of $8,720. Using an industry benchmark 40% cost-to-charge ratio, this analysis indicates that hospitals incur incremental unnecessary costs of $3,488 per false positive result. These costs include antibiotic therapies, diagnostic imagining, extended length of stay and other tests/treatments that are administered based on false positive blood culture results.
Accordingly, the impact of reducing false positive rates by even fractions of a percent represents meaningful opportunity for financial, patient care and overall quality improvement.
The chart below depicts annual cost savings associated with a 1% reduction in false positive blood culture rate based on various volumes.
| Annual Cost Savings
|Annual Cost Savings Based on Volume
Note: the incremental costs identified in this study do not take the opportunity cost of incremental bed day occupation into account.