Several blood tests can help in the diagnosis of IBD, such as C-reactive protein (CRP), Erythrocyte Sediment Rate (ESR), Saccharomyces cerevisiae antibodies (ASCA), and perinuclear anti-neutrophilic cytoplasmic antibodies (p-ANCA), but none can definitively diagnose IBD. The gene discussed is CRP; the disease is irritable bowel syndrome.