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Decision Rule to Identify Patient Who Should Have a Blood Culture

Purpose: To determine if a patient in the Emergency Department should have a blood culture drawn using the decision rule of Shapiro et al.

Description

Shapiro et al developed criteria for which patients should have a blood culture drawn. This can help to reduce unnecessary testing. The authors are from Beth Israel Deaconess Medical Center, Brigham and Women's Hospital and Harvard Medical School in Boston.


 

Parameters:

(1) suspicion of endocarditis

(2) temperature

(3) indwelling vascular catheter

(4) age in years

(5) chills

(6) vomiting

(7) hypotension (systolic blood pressure < 90 mm Hg)

(8) white blood cell count

(9) percent bands in the peripheral blood smear

(10) platelet count

(11) serum creatinine

 

Parameter

Finding

Points

suspect endocarditis

no

0

 

yes

3

temperature

> 39.4°C

3

 

38.3 to 39.3°C

1

 

< 38.3°C

0

indwelling vascular catheter

absent

0

 

present

2

age in years

<= 65 years of age

0

 

> 65 years of age

1

chills

absent

0

 

present

1

vomiting

absent

0

 

present

1

systolic blood pressure

>= 90 mm Hg

0

 

< 90 mm Hg

1

white blood cell count

<= 18,000 per µL

0

 

> 18,000 per µL

1

percent bands

0 to 5%

0

 

>= 6%

1

platelet count

< 150,000 per µL

1

 

>= 150,000 per µL

0

serum creatinine

<= 2.0 mg/dL

0

 

> 2.0 mg/dL

1

 

where:

• The 3 items with points >= 2 are called major criteria while the others are considered minor. The presence of 1 major or 2 minor is sufficient to justify a blood culture.

 

total score =

= SUM(points for all 11 parameters)

 

Interpretation:

• minimum score: 0

• maximum score: 16

• A patient with a score >= 2 should have a blood culture drawn.

 

Performance:

• The sensitivity is high (97%) while the specificity is low (29%).

• The test was able to reduce the number of blood cultures performed by 27%.

 


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Specialty

Objective

ICD-10