Blood culture (BCx) contamination is a common, costly, and preventable problem which can cause confusion for clinicians. Contaminated BCx (CBCx) leads to unnecessary hospitalization, additional testing/consultation, and unnecessary treatment. The maximum acceptable percent of CBCx is 3%. Some hospital areas have higher contamination rates than others (e.g. Emergency Department - ED). Our Antimicrobial Stewardship Program was interested in decreasing the inappropriate use of antibiotics (usually vancomycin) associated with CBCx. The most common CBCx organisms were aerobic Gram-positive cocci, with the most common organism identified being S. epidermidis. Identified issues resulting in CBCx included improper skin preparation and accessing a peripheral venous catheter for blood cultures. For the years 2010-2012, the ED was responsible for 33-61%, 29-74%, and 31-76% of the monthly total CBCx, respectively. We evaluated the time of day CBCx were drawn during 2010-2012, and CBCx occurrence rose beginning at 08:00, peaked at 14:00, and declined significantly 22:00 during these three years, nearing the staff shift change. Hospital and ED costs associated with CBCx were estimated, as well as costs incurred by the microbiology lab and pharmacy. Estimated hospital cost of CBCx for the three years averaged $1,893,830, with the ED accounting for $929,500 (49%). The most commonly used antibiotic to treat CBCx was vancomycin, with an annual average hospital cost of $6,887 for the last three years evaluated. Projected average hospital savings by reducing the occurrence of CBCx from the ED during these three years by 20% and 30% were $185,166 and $278,670 respectively.

Abstract

Blood culture (BCx) contamination is a common, costly, and preventable problem which can cause confusion for clinicians and leads to unnecessary hospitalization, additional testing and consultation, and unnecessary treatment. The maximum acceptable percent of contaminated (CBCx) is 3% (Clinical and Laboratory Standards - CLSI, College of American Pathologist - CAP). Some hospital areas have historically higher contamination rates than others (e.g. ED). In 1991, Bates reported that the average inpatient with a contaminated blood culture (CBCx) accumulated $4385 ($5506 in 2004 adjusted for inflation) in excess charge and stayed in the hospital 4.5 additional days. Alahmadi et al in 2011 discovered in a retrospective case-controlled study an excess of 5.4 days of hospitalization and total costs attributable to contaminated blood cultures was $7,502 - yearly costs for 142 CBCx: 1372 additional hospital days and $1,905,572 in associated costs. Our Antimicrobial Stewardship Program was interested in the potential impact of CBCx to our hospital, ED, and laboratory as well as decreasing inappropriate antibiotic use.

Introduction

We reviewed the CBCx occurrence during the years 2008-2012 to determine if our hospital CBCx rate exceeded the 3% acceptable rate. For years 2010-2012, the hospital area where CBCx were drawn, as well as the time of day of collection, was determined. The cost of laboratory evaluation of CBCx was made as well as the estimated costs of CBCx impacting the laboratory, ED, and hospital for years 2010-2012 were determined.

Materials & Methods

Hospital Contaminated Blood Culture Rate FY 2008 - 2012 (Acceptable contamination rate ≤3%)

Results

Blood Culture Contamination Rate FY 2012 ED Rate 33% - 62% of total contaminated BCx

Our review of the occurrence of CBCx within our hospital illustrate the potential to provide consistent compliance with the recommended ≤3% occurrence CBCx rate as well as decrease the inappropriate use of antibiotics (usually vancomycin) pending the identification of the organism associated with the CBCx. The most common CBCx organisms were aerobic Gram-positive cocci, with the most common organism identified being Staphylococcus epidermidis. Identified issues resulting in CBCx included improper skin preparation and accessing a peripheral venous catheter for blood cultures. For the years 2010-2012, the Emergency Department (ED) was responsible for 33-61%, 29-74%, and 31-76% of the monthly total CBCx, respectively. The time of day CBCx were drawn during 2010-2012 were determined, with CBCx occurrence increasing beginning at 08:00, peaked at 14:00, and declined significantly 22:00 during these three years, nearing the ED staff shift change. Hospital and ED costs associated with CBCx were estimated, as well as costs incurred by the microbiology lab and pharmacy. The overall estimated hospital cost of CBCx for the three years averaged $1,893,830, with the ED accounting for $929,500 (49%). The most commonly used antibiotic to treat CBCx was vancomycin, with an annual average hospital cost of $6,887 for the last three years evaluated. Projected average hospital savings by reducing the occurrence of CBCx from the ED during these three years by 20% and 30% were $185,166 and $278,670 respectively. Reducing the occurrence of CBCx may result in significant hospital savings from inappropriate hospital admissions, additional laboratory costs, and overuse of antibiotics.

1. Alahmadi YM, et al. Clinical and economic impact of contaminated blood cultures within the hospital setting. J Hosp Infect 77:233-236 2011.

2. Parada JP et al. Effects of type and level of training on variation in physician knowledge in the use and acquisition of blood cultures: a cross sectional survey. BMC Infect Dis 5:71-79 2005.

3. Weinstein MP, Blood culture contamination : persisting problems and partial success. J Clin Microbiol 41:2275-2278 2003.

4. Souvenir D, et al. Blood cultures positive for coagulase-negative staphylococci; antisepsis, pseudobacteremia, and therapy of patients. J Clin Microbiol 36: 1923-1926 1998.

5. Weinbaum FI et al. Doing it right the first time: quality improvement and the contaminated blood culture. J Clin Microbiol 35:563-565 1997.

6. Bates DW, et al. Contaminant blood cultures and resource utilization: the true consequences of false positive results. JAMA 265:365-369 1991.

Conclusion

References

Reduction in Contaminated Blood Culture Rates and Associated Costs as an Antimicrobial Stewardship Program Activity

John Toney MD1,2, Narla Fries CLS, MT(ASCP)1, Rey Rivera MD1, Stephen Mastorides MD1, Richard Oehler MD1,2, and Sandra Gompf MD1,2 1James A. Haley Veterans' Hospital, Tampa, FL 2University of South Florida, Tampa, FL

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

3.5%

4.0%

4.5%

5.0%

% c

onta

min

ated

BC

x

2008 2009 2010 2011 2012

Time of Day (24 H Clock)

Contaminated Blood Cultures in the ED – Time of Day Drawn FY 2010-2012

Poster #167

Month FY 2012 FY 2011 FY 2010 # Contam BCx ED Cost of evaluation # Contam

BCx ED Cost of evaluation # Contam BCx ED Cost of evaluation

OCT 9 $ 1,050.93 11 $ 1,284.47 9 $ 1,050.93 NOV 16 $ 1,868.32 10 $ 1,167.70 18 $ 2,101.86 DEC 12 $ 1,401.24 15 $ 1,751.55 28 $ 3,269.56 JAN 11 $ 1,284.47 20 $ 2,335.40 13 $ 1,518.01 FEB 9 $ 1,050.93 8 $ 934.16 13 $ 1,518.01 MAR 16 $ 1,868.32 5 $ 583.85 21 $ 2,452.17 APR 13 $ 1,518.01 20 $ 2,335.40 14 $ 1,634.78 MAY 23 $ 2,685.71 14 $ 1,634.78 11 $ 1,284.47 JUN 12 $ 1,401.24 8 $ 934.16 22 $ 2,568.94 JUL 13 $ 1,518.01 9 $ 1,050.93 13 $ 1,518.01 AUG 8 $ 934.16 25 $ 2,919.25 9 $ 1,050.93 SEP 15 $ 1,751.55 11 $ 1,284.47 23 $ 2,685.71

TOTALS 157 $ 18,332.89 156 $ 18,216.12 194 $ 22,653.38 Vanco Tx for 48h** $ 3,140.00 $ 3,120.00 $ 3,880.00

CBCx & Tx Totals $ 21,472.89 $ 21,336.12 $ 26,533.38

*Microbiology tech cost ($116.77) - does not include setups, nursing time, additional BCx orders, admission for management of “positive blood culture”, etc. ** $20 for 2 days treatment

Lab/Pharmacy Minimal Costs of ED Contaminated Blood Cultures*

Month FY 2012 FY 2011 FY 2010 # Contam BCx ED Cost of evaluation # Contam

BCx ED Cost of evaluation # Contam BCx ED Cost of evaluation

OCT 9 $ 49,500 11 $ 60,500 9 $ 49,500 NOV 16 $ 88,000 10 $ 55,000 18 $ 99,000 DEC 12 $ 66,000 15 $ 82,500 28 $ 154,000 JAN 11 $ 60,500 20 $ 110,000 13 $ 71,500 FEB 9 $ 49,500 8 $ 44,000 13 $ 71,500 MAR 16 $ 88,000 5 $ 27,500 21 $ 115,500 APR 13 $ 71,500 20 $ 110,000 14 $ 77,000 MAY 23 $ 126,500 14 $ 77,000 11 $ 60,500 JUN 12 $ 66,000 8 $ 44,000 22 $ 121,000 JUL 13 $ 71,500 9 $ 49,500 13 $ 71,500 AUG 8 $ 44,000 25 $ 137,500 9 $ 49,500 SEP 15 $ 82,500 11 $ 60,500 23 $ 126,500

TOTALS 157 $ 863,500 156 $ 858,000 194 $ 1,067,000

*Average of literature reported overall cost of one contaminated blood culture to hospital - $5,500

Total Hospital Costs of ED Contaminated Blood Cultures*

Month FY 2012 FY 2011 FY 2010 # Contam BCx ED Cost of evaluation # Contam

BCx ED Cost of

evaluation # Contam BCx ED Cost of evaluation

TOTALS 157 $ 18,332.89 156 $ 18,216.12 194 $ 22,653.38 Vanco Tx for

48h** $ 3,140.00 $ 3,120.00 $ 3,880.00

Tx Totals $ 21,472.89 $ 21,336.12 $ 26,533.38 20% reduction 126 $ 14,713.02 125 $ 14,596.25 155 $ 18,099.35 Vanco Tx for

48h** $ 2,520.00 $ 2,500.00 $ 3,100.00

Tx Totals $ 17,233.02 $ 17,096.25 $ 21,199.35 30% reduction 110 $ 12,844.70 109 $ 12,727.93 136 $ 15,880.72 Vanco Tx for

48h** $ 2,200.00 $ 2,180.00 $ 2,720.00

Tx Totals $ 15,044.70 $ 14,907.93 $ 18,600.72 20% reduction

annual savings

31 $ 4,239.87 31 $ 4,239.87 39 $ 5,334.03

30% reduction annual savings

47 $ 6,428.19 47 $ 6,428.19 58 $ 7,932.66

*Microbiology tech cost ($116.77) - does not include setups, nursing time, additional BCx orders, admission for management of “positive blood culture”, etc. ** $20 for 2 days treatment

Lab/Pharmacy Minimal Costs of ED Contaminated Blood Cultures*

Total Hospital Costs of ED Contaminated Blood Cultures*- Comparison 2010-2012 if 20% to 30% reduction in BCx

contamination

Month FY 2012 FY 2011 FY 2010 # Contam BCx ED

Cost of evaluation

# Contam BCx ED Cost of evaluation # Contam

BCx ED Cost of evaluation

TOTALS 157 $ 863,500 156 $ 858,000 194 $ 1,067,000 20% reduction 126 $ 693,000 125 $ 687,500 155 $ 852,500 30% reduction 110 $ 605,000 109 $ 599,500 136 $ 748,000 20% reduction annual savings 31 $ 170,500 31 $ 170,500 39 $ 214,500

30% reduction annual savings 47 $ 258,500 47 $ 258,500 58 $ 319,000

*Average of literature reported overall cost of one contaminated blood culture to hospital - $5,500

39%

33% 40%

43%

61%

44% 45%

35% 62%

%= number of contaminated BCx sent from area as a per cent of all contaminated BCx that month

1151 1209 1253 1081 1200 1087 1124 1101 987

28 27

40

30

38

27 29

23 24

45%

53%

55%

1151 1051 1103

20

32

22

CBCx - contaminated blood cultures BCx - blood cultures

John.Toney@va.gov