Background: Nowadays, Primary Immune Thrombocytopenia diagnosis (ITP) is based on identifying 
a platelet count < 100 × 109
/L and exclusion of other causes of thrombocytopenia. Currently , there 
are no standard tests or biomarkers to diagnose primary ITP or predict its prognosis and response to 
treatment. Objectives :Our study aims at assessing the role of High sensitivity C- Reactive Protein in 
ITP pathogenesis and in the prediction of the disease behavior and response to 
treatment. Methods: Our study was done on four groups: Group I consisted of 28 newly diagnosed 
ITP patients in whom data were recorded before and after treatment with corticosteroids, Group II
had 10 corticosteroid responder ITP patients, Group III contained 10 corticosteroid resistant ITP 
patients , while Group IV had 18 age and sex matched healthy control subjects to whom the previous 
three groups were compared. Results: Newly diagnosed ITP patients in our study were found to have 
significantly higher levels of High sensitivity CRP before treatment with corticosteroids compared to 
the same patients levels after treatment with corticosteroids, p value <0.001. Also, Comparing High 
sensitivity C- Reactive Protein levels in the four studied groups showed that they were higher in 
Corticosteroid resistant ITP patients (Group III) compared to the other three groups. p value 
<0.001. Conclusion: High sensitivity CRP level was found to be associated with ITP resistance to 
corticosteroid treatment, and it was found to decrease in the newly diagnosed patients after starting 
treatment by corticosteroids.