CRP and granulomatosis with polyangiitis: In patients with suspected GPA, the following routine laboratory tests should be performed: complete blood count with differential and blood smear, renal function (creatinine with eGFR and urea), electrolytes, liver enzyme, coagulation tests (with D-dimer), erythrocyte sedimentation rate (ESR) and CRP, and complete urinalysis with urinary sediment and 24-h proteinuria collection (73).