Clinical Relevance

C-reactive protein (CRP) is the best known among the acute-phase proteins, a group of proteins whose concentration increases in blood as a response to inflammatory disorders (acute-phase response). CRP is normally present in low concentration in blood of healthy individuals (< 5 mg/L). It is elevated up to 500 mg/L in acute inflammatory processes associated with bacterial infections, postoperative conditions or tissue damage already after 6 hours reaching a peak at 48 hours. The measurement of CRP represents a useful laboratory test for the detection of acute infection as well as for monitoring inflammatory processes; among others in acute rheumatic and gastrointestinal diseases. CRP testing shows various advantages in comparison to the erythrocyte sedimentation rate (ESR) and the leukocyte count. In fact, it is more sensitive, the increase occurs earlier and its levels return to the reference range more rapidly after healing.

Advantages of CRP

Advantages of DiaSys CRP ISDisadvantages of Erithrocyte sedimentation rate (ESR)Disadvantages of latex agglutination slides
Limit of detection5 mg/L (capillary blood)
2 mg/L (plasma)
Not applicable> 6 – 10 mg/L (serum)
Quantitative?Quantitative resultsNot applicableQualitative or semi-quantitative results, no exact quantification possible
Differentiation of borderline cases from positive and negative casesTrue differentiationNo true differentiation
Unspecific screening
No true differentiation
Reaction time after start of inflammationEarly
4 - 6 h
24 - 48 h
4 - 6 h
Suitability for therapeutic monitoringGiven, fast reactionLimited, slow Limited
ProcessingFully automatedManual and automated
Person dependent visual assessment (manual)
Vertical position of sample or sample tray (manual)
Person dependent visual assessment
StabilityIn serum and plasma:
15 days at 20 - 25°C
Highly influenced by temperature (correct results only at 23°C)
Sample stability only 2h at room temperature
In serum and plasma:
15 days at 20 - 25°C
Contamination riskMinimizedDependent on test tubeHigh
TraceabilityInternational reference material ERM-DA474/IFCCNoneTest dependent
Control materialTruLab CRP, two different levelsNoneOnly positive and negative controls