Best Practices in Blood Cultures: Effective QA. Michael Mitchell, MD, F(CAP) Department of Hospital Laboratories, UMass Memorial Medical Center Worcester, MA. Introduction and Overview. Review issues related to bacteremia and fungemia Review general principles of QA monitors
Michael Mitchell, MD, F(CAP)
Department of Hospital Laboratories,
UMass Memorial Medical Center
Informative analysis (insight into problems)
Subject to intervention
Don’t choose too many!
Review External Benchmarks
Provide Educational Resources
On-site visits to Units
Stress critical aspects for Quality
Quarterly monitoring and reporting
Avoid collection through lines.
Sterilize of each “barrier” crossed
Collection of multiple independent cultures; Avoid excessive cultures
Recognize of probable contaminants
M47 discusses several methods for effective skin decontamination:
The risk of a patient having a contaminated blood culture increases arithmetically with the number of cultures obtained.
Increased antibiotic treatment
Increased numbers of laboratory tests
Complications of above
You have to get bugs in the broth to get a positive blood culture!
Typical bacteremia 1 cfu/mL + log10.
Linear increased detection as inoculum increases.
How do we get volume?
Volume of blood per bottle
Number of bottles per culture
Number of cultures per evaluation
Back-to-back cultures may be collected.
Wait 48 to 72 hours before repeating evaluation with additional blood cultures.
Consider other sources of infection or diagnostic techniques.
CLSI Recommendation: For patients with low prior probability of bacteremia or fungemia, surveillance cultures or extensive test of cure assessments are not recommended.
Aerobic Bottle Result
Anaerobic Bottle Result
Interpretation (TP, FP)
Label bottles so that those from a single collection can be accurately paired
Never submit bottles from different collections as a single culture
Is it real?
Is it sustained?
Does it stratify by location or time?
Change in patient population?
Change in any aspect of process?Assess/Seal Cracks