From the Guidelines
Sensitivity and Specificity of CRP in Diagnosing Neonatal Sepsis
The sensitivity and specificity of C-reactive protein (CRP) in diagnosing neonatal sepsis are approximately 68-92% and 40-67%, respectively, although these values can vary based on the context and population studied 1.
- A CRP level is generally considered indicative of sepsis when it exceeds certain thresholds, but the exact value can depend on various factors including the clinical context and the laboratory methods used.
- Optimal diagnostic accuracy is achieved when CRP levels are combined with clinical evaluation and other laboratory markers.
- Serial measurements of CRP, with a significant increase in levels over 24-48 hours, may also aid in the diagnosis of neonatal sepsis, particularly in cases where initial levels are borderline or inconclusive 1. Some studies suggest that a CRP level of 50 mg/l or higher had a sensitivity of 98.5% and specificity of 75% in identifying probable or definite sepsis in an ICU population 1, but these values may not directly apply to neonatal sepsis due to differences in population and context. It's also worth noting that while CRP can be useful in diagnosing sepsis, it has low specificity and cannot differentiate bacterial infections from non-infectious causes of inflammation, making it just one part of a comprehensive diagnostic approach 1.
From the Research
Sensitivity and Specificity of C-Reactive Protein (CRP) in Diagnosing Neonatal Sepsis
- The sensitivity and specificity of CRP in diagnosing neonatal sepsis have been evaluated in several studies 2, 3, 4, 5, 6.
- A meta-analysis found that the pooled sensitivity and specificity of CRP were 71% and 86%, respectively 3.
- Another study found that the sensitivity and specificity of CRP were 95.7% and 82.4%, respectively, with an area under the curve (AUC) of 0.948 6.
- The sensitivity of CRP has been reported to be higher when serial measurements are used, with a sensitivity of 97.8% and 98.1% for proven or probable sepsis in early-onset and late-onset episodes, respectively 5.
- The specificity of CRP has been reported to be lower when a single measurement is used, with a specificity of 64.6% and 61.5% for proven or probable sepsis and proven sepsis, respectively, in early-onset episodes 5.
Factors Affecting the Sensitivity and Specificity of CRP
- The cutoff value of CRP can affect its sensitivity and specificity, with a cutoff value > 10 mg/L having high sensitivity and specificity 2.
- The timing of CRP measurement can also affect its sensitivity and specificity, with serial measurements having higher sensitivity and specificity than a single measurement 5.
- The presence of other inflammatory conditions, such as post-operative patent ductus arteriosus ligation, intracerebral hemorrhage, and post-resuscitation with chest compression, can cause false positive CRP results 4.
Comparison with Other Biomarkers
- CRP has been compared with other biomarkers, such as procalcitonin (PCT) and presepsin, in the diagnosis of neonatal sepsis 2.
- The combination of PCT and CRP or presepsin alone has been found to improve the accuracy of diagnosis of neonatal sepsis 2.
- CRP has been found to have moderate accuracy in the diagnosis of neonatal sepsis, with an AUC of 0.8535 3.