Michael Mitchell, MD, F(CAP)Department of Hospital

Laboratories,UMass Memorial Medical Center

Worcester, MA

Best Practices in Blood Cultures: Effective QA

Introduction and OverviewReview issues related to

bacteremia and fungemiaReview general principles of QA

monitorsQA monitors for routine blood

culturesData analysisResponses and interventions

Bacteremia and Fungemia

Significant Bacteremia

Bugs in > Bugs outEndovascular 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 factorsHost underlying medical conditionsNosocomial factors

Impact of True Positive CulturesProvides therapeutic and

prognostic insight

Informs a general approach to careAntimicrobialsCritical care interventionsInvestigation of sources

Impact of True Positive CulturesProvides a pathogen for further

testingAnother indicator of prognosisSusceptibility testingTesting for specific virulence factor

Stocked organisms

Impact of Contaminated Cultures

Costs to PatientAdditional testingUnneeded antimicrobial therapyAdditional LOSComplications of the above!

Impact of Contaminated Cultures

Costs to the Institution$10 to $40 thousand dollars per episode of care!

Patient safety and satisfactionPublic Reporting

Quality assurance: general issues

Quality Monitors

PROCESSAnalyticalPre-analyticalPost-analytical

DATA → INFORMATION

What is Monitored and Reported

Will Improve…

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 objectiveCollection must be achievableInterpretable and informativeAllow for relevant stratificationActionable

Developing Effective Monitors

Define critical elements in processDetermine informative dataDetermine how data will be analyzedDetermine potential “interventions”Collectable over time; analyze effects of

interventionsDetermine “Life Cycle”?

Microbiologists and Hospital QAAccess to patient-specific and

cumulative dataComfortable with computer

databases and analytical toolsInsight into pre-, post- and

analytical aspects of qualityExperience working in multi-

disciplinary teamsUse of Standards is standard

Choose indicators wisely

Objective dataEasily capturedInformative analysis (insight into problems)Subject to intervention

Don’t choose too many!

Specific QA monitors for blood cultures

Resources

CLSI document M-47A: Principles and Procedures for Blood Cultures; Approved Guideline

Cumitech 1C Blood Cultures IVVarious publications (See

Reference pages below)

Local process analysis—Ishikawa diagram

M-47A Quality ComponentsPre-Analytical

Patient EvaluationTest Selection and OrderingSample Collection and Inoculation

Sample TransportSample Receipt and Initial Processing

M-47A Quality ComponentsAnalytical

Platforms and procedures for detection

Identification of IsolatesSusceptibility testing protocolsVerification of resultsInterpretation of results

M-47A Quality ComponentsPost-Analytical

ReportingRecord ManagementConsultation

UMMMC Quality Monitors

True Positive and Contamination Rates

Single Bottle CulturesSingle Culture EvaluationsClinically Uninformative Cultures

Stratification by Location Harmonize with CR-BSI Activities

UMMMC Blood Culture QA InitiativeLaboratory

Microbiology, Information Services, Phlebotomy, Quality Management

Critical Care OperationsInfection ControlPatient Safety/Quality

Management

NPR Report

Lab#MR#Patient nameDate and time of collectionLocation of collectionRequesting MDCulture results

Activities Related to Blood Culture Quality

Review External BenchmarksProvide Educational ResourcesOn-site visits to UnitsStress critical aspects for QualityQuarterly monitoring and reporting

Specificity

Avoid collection through lines.Sterilize of each “barrier” crossedCollection of multiple independent

cultures; Avoid excessive culturesRecognize 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 LOSIncreased antibiotic treatmentIncreased numbers of laboratory

testsComplications of above

Sensitivity: Volume of blood inoculatedYou 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 bottleNumber of bottles per cultureNumber 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 RecommendationEach 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

If you think about doing a blood culture,

DO TWO

Inoculum Volume for Adults

Data analysis

Paper is sooo Last MileniumReports

Relevant FieldsUnformated text fileImportable into data

management program

Blood Culture QA Data

Lab #Patient NamePatient MR#Patient AgeCollection DateCollection TimeCollection

Location

Submitting MDAerobic Bottle

ResultAnaerobic

Bottle ResultInterpretation

(TP, FP)

Interpretation of Positive Cultures

Species isolatedOther co-isolated organismsIsolation 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

Questionable Positive

SPEC# DATE TIME BOTTLE RESULT SIG

1 11/21/2005 1706 RESIN NO GROWTH Q

1 11/21/2005 1706 ANAEROBIC STAPH. SPECIES, (NOT AUREUS) Q

2 11/21/2005 1706 ANAEROBIC NO GROWTH Q

2 11/21/2005 1706 RESIN STAPH. SPECIES, (NOT AUREUS) Q

COLLECTED

SUBMITTED

1-1 2-2

1-2 2-1

STERILE CONTAM

CONTAMCONTAM

How Have We Done?

Performance Over Time

2006 2010# PTS 378 553

Pts w/ >10 Cultures 33 10Pts w/ >20 Cultures 8 1

# EVALS 886 993# SINGLE EVALS 255 286% SINGLE EVALS 28.8% 28.8%

Performance Over Time

2006 2010# CULTS 1565 1740

# TP 91 63% TP CULTS 5.8% 3.6%

# FP 66 34% FP CULTS 4.2% 1.9%

# PTS W/ ANY FP 60 30% PTS W/ ANY FP 15.9% 5.4%# PTS W/ ANY TP 41 33% PTS W/ ANY TP 10.8% 6.0%

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Responses and interventions

Assess/Seal Cracks

If a monitor exceeds threshold:Is it real?Is it sustained?Does it stratify by location or time?Change in patient population?Change in any aspect of process?

Interventions

Assess for “breaks” in processRe-education, general or site-

focusedStress: “Take time to do it right!”Establish phlebotomy teamsCreate barriers against poor

quality practices

Summary

QA activities related to blood cultures are critical for patient outcome and cost-effective care

Objective, actionable monitors are part of the laboratory’s QA activities

A committed multi-disciplinary team is involved

Significant improvements have been achieved, but challenges continue

Thank You!

Contact InformationMichael J. Mitchell, MD, FCAP

Director, Microbiology ServicesDepartment of Hospital LaboratoriesUMass Memorial Medical Center365 Plantation Street, Room 279Worcester, MA 01605Phone: 774-442-9630mitchelm@ummhc.org

References Baron EJ, et al. Cumitech 1C: Blood Cultures IV. 2005. Cockerill FR, et al. Optimal Testing Parameters for Blood

Cultures. 2004. Clin Infect Dis 38: 1724-30. Connell TG, et al. How Reliable Is a Negative Blood

Culture Result? Volume of Blood Submitted for Culture in Routine Practice in a Children’s Hospital. 2007. Pediatrics 119: 891-6.

Dwivedi S, et al. Discarding the Initial Aliquot of Blood Does Not Reduce Contamination Rates in Intravenous-Catheter-Drawn Blood Cultures. 2009. JCM 47: 2950-1.

Everts RJ, et al. Contamination of Catheter-Drawn Blood Cultures. 2001. JCM 39: 3393-94.

References 2 Gander RM, et al. Impact of Blood Cultures Drawn by

Phlebotomy on Contamination Rates and Health Care Costs in a Hospital Emergency Department. 2009. JCM 47: 1021-24.

Hall KK and JA Lyman. Updated Review of Blood Culture Contamination. 2006. Clin Microbiol Rev 19: 788-802.

Ilstrup DM and JA Washington 2d. The importance of volume of blood cultured in the detection of bacteremia and fungemia. 1983. Diagn Microbiol Infect Dis. 1: 107-10.

Levin PD, et al. Routine Surveillance Blood Cultures: Their Place in the Management of Critically Ill Patients. 1997. J Infect 35: 125-8.

References 3 Mermel LA and DG Maki. Detection of Bacteremia in

Adults: Consequences of Culturing an Inadequate Volume of Blood. 1993. Ann Intern Med 119: 270-272.

Mirrett S, et al. Relevance of the Number of Positive Bottles in Determining Clinical Significance of Coagulase-Negative Staphylococci in Blood Cultures. 2001. JCM 39: 3279-81.

Nielsen J, et al. Poor Value of Surveillance Cultures of Prediction of Septicaemia Caused by Coagulase-negative Staphylococci in Patients Undergoing Haemodialysis with Central Venous Catheters. 1998. Scand J Infect Dis 30: 569-72.

Patel R, et al. Optimized Pathogen Detection with 30- Compared to 20-Milliliter Blood Culture Draws. 2011. JCM 49: 4047-4051.

References 4 Seifert H. The Clinical Importance of Microbiological

Findings in the Diagnosis and Management of Bloodstream Infections. 2009. Clin Infect Dis 48: S238-45.

Weinbaum FI, et al. Doing It Right the First Time: Quality Improvement and the Contaminant Blood Culture. 1997. JCM 35: 563-65.

Weinstein MP, et al. The Clinical Significance of Positive Blood Cultures in the 1990s… 1997. Clin Infect Dis 24: 584-602.

Wilson ML, et al. CLSI document M47-A Principles and Procedures for Blood Cultures; Approved Guideline. 2007.

References 5 Yokoe DS, et al. Simplified Surveillance for Nosocomial

Bloodstream Infections. 1998. Infect Control Hosp Epidem 19: 657-60.

Zwang O and RK Albert. Analysis of Strategies to Improve Cost Effectiveness of Blood Cultures. 2006. J Hosp Med 1: 272-6.