Patient selection: febrile pediatric patient from 1 month to 18 years of age with different temperature thresholds
Study: meta-analysis
Parameters:
(1) procalcitonin
(2) C-reactive protein (CRP)
|
Procalcitonin Concentration
|
Serious Infection
|
|
< 0.5 ng/mL (µg/L)
|
probably not
|
|
0.5 to 2.0 ng/mL
|
indeterminate
|
|
> 2 ng/mL
|
probably
|
|
CRP Concentration
|
Serious Infection
|
|
< 20 mg/L
|
probably not
|
|
20 to 80 mg/L
|
indeterminate
|
|
> 80 mg/L
|
probably
|
A serious infection was defined as either procalitonin > 2 ng/mL OR CRP > 80 mg/L.
A serious infection was ruled uot if either procalcitonin < 0.5 ng/mL OR CRP < 20 mg/L (an AND operation might be more specific).
The white blood cell count was not as useful for classifying the patient.
Performance:
• The sensitivity for the rule-in was > 90% with a specificity of 40-50%.
• The sensitivity of the rule-out was > 80% with specificity 70%.
Limitations:
• The methods of analysis and the normal reference ranges were not stated.
• The time of sample collection relative to duration of the illness will affect the concentration of the analyte. A sample drawn too early or too late may not be as predictive as one collected at the time of peak illness.
• The prevalence of serious infection in children enrolled in the studies (1 in 5) was significantly higher than that seen in primary care (1 in 150).
