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 • QA monitors for routine blood cultures • Data analysis • Responses and interventions
Significant Bacteremia • Bugs in > Bugs out • Endovascular vs. extra-vascular infection • Bacteremia may be continuous or intermittent • “Organism load” (cfu/mL) is low
Clinical Implications • Bacteremic infections are increasing • Bacteremic infection result in high morbidity and mortality • Isolates are more likely to be resistant • Bacteremic infection may cause metastatic, localized complications
Risk Factors • Pathogen virulence factors • Host underlying medical conditions • Nosocomial factors
Impact of True Positive Cultures • Provides therapeutic and prognostic insight • Informs a general approach to care • Antimicrobials • Critical care interventions • Investigation of sources
Impact of True Positive Cultures • Provides a pathogen for further testing • Another indicator of prognosis • Susceptibility testing • Testing for specific virulence factor • Stocked organisms
Impact of Contaminated Cultures • Costs to Patient • Additional testing • Unneeded antimicrobial therapy • Additional LOS • Complications of the above!
Impact of Contaminated Cultures • Costs to the Institution • $10 to $40 thousand dollars per episode of care! • Patient safety and satisfaction • Public Reporting
Quality Monitors • PROCESS • Analytical • Pre-analytical • Post-analytical • DATA → INFORMATION
Effective QA Programs • Harmonize Lab’s and Institution’s QA activities • Choose Indicators that reflect quality • Choose Indicators for a assessment of all aspects of analytical process • Engage stakeholders
Effective QA Monitor Data • Measurable, reliable and objective • Collection must be achievable • Interpretable and informative • Allow for relevant stratification • Actionable
Developing Effective Monitors • Define critical elements in process • Determine informative data • Determine how data will be analyzed • Determine potential “interventions” • Collectable over time; analyze effects of interventions • Determine “Life Cycle”?
Microbiologists and Hospital QA • Access to patient-specific and cumulative data • Comfortable with computer databases and analytical tools • Insight into pre-, post- and analytical aspects of quality • Experience working in multi-disciplinary teams • Use of Standards is standard
Choose indicators wisely Objective data Easily captured Informative analysis (insight into problems) Subject to intervention Don’t choose too many!
Resources • CLSI document M-47A: Principles and Procedures for Blood Cultures; Approved Guideline • Cumitech 1C Blood Cultures IV • Various publications (See Reference pages below) • Local process analysis—Ishikawa diagram
M-47A Quality Components • Pre-Analytical • Patient Evaluation • Test Selection and Ordering • Sample Collection and Inoculation • Sample Transport • Sample Receipt and Initial Processing
M-47A Quality Components • Analytical • Platforms and procedures for detection • Identification of Isolates • Susceptibility testing protocols • Verification of results • Interpretation of results
M-47A Quality Components • Post-Analytical • Reporting • Record Management • Consultation
UMMMC Quality Monitors • True Positive and Contamination Rates • Single Bottle Cultures • Single Culture Evaluations • Clinically Uninformative Cultures • Stratification by Location • Harmonize with CR-BSI Activities
UMMMC Blood Culture QA Initiative • Laboratory • Microbiology, Information Services, Phlebotomy, Quality Management • Critical Care Operations • Infection Control • Patient Safety/Quality Management
NPR Report • Lab# • MR# • Patient name • Date and time of collection • Location of collection • Requesting MD • Culture results
Activities Related to Blood Culture Quality Review External Benchmarks Provide Educational Resources On-site visits to Units Stress critical aspects for Quality Quarterly monitoring and reporting
Specificity Avoid collection through lines. Sterilize of each “barrier” crossed Collection of multiple independent cultures; Avoid excessive cultures Recognize of probable contaminants
Skin Decontamination M47 discusses several methods for effective skin decontamination: • Tincture of iodine or chlorhexidine gluconate • 30 second abrasive scrub
Specificity: Number of Cultures per Evaluation The risk of a patient having a contaminated blood culture increases arithmetically with the number of cultures obtained.
The Cost of Contaminated Blood Culture is High Increased LOS Increased antibiotic treatment Increased numbers of laboratory tests Complications of above
Sensitivity: Volume of blood inoculated 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.
Sensitivity How do we get volume? Volume of blood per bottle Number of bottles per culture Number of cultures per evaluation
Culture Timing 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.
Prior Probability of Bacteremia or Fungemia CLSI Recommendation: For patients with low prior probability of bacteremia or fungemia, surveillance cultures or extensive test of cure assessments are not recommended.
Evaluation Recommendation • Each blood culture: • Collect 20 mL by venipuncture for each culture • Inoculate 10mL of blood each into an aerobic and an anaerobic bottle • Immediately collect a second, independent blood culture
Paper is sooo Last Milenium • Reports • Relevant Fields • Unformated text file • Importable into data management program
Blood Culture QA Data Lab # Patient Name Patient MR# Patient Age Collection Date Collection Time Collection Location Submitting MD Aerobic Bottle Result Anaerobic Bottle Result Interpretation (TP, FP)
Interpretation of Positive Cultures • Species isolated • Other co-isolated organisms • Isolation of the organism from other independent blood cultures or infected sites
Blood Culture Pairs Label bottles so that those from a single collection can be accurately paired Never submit bottles from different collections as a single culture
COLLECTED 1-1 2-2 STERILE CONTAM 2-1 1-2 SUBMITTED CONTAM CONTAM