This includes infectious causes for scleritis, including tuberculosis (PPD/QuantiFERON-TB Gold), syphilis (RPR/FTA-ABS), and Lyme disease, and non-infectious causes for scleritis, including rheumatoid arthritis (ANA, RF, anti-CCP), granulomatosis with polyangiitis (ANCA), sarcoidosis (chest X-ray, ACE, lysozyme), and non-specific inflammation (CBC, ESR, CRP). Here, CRP is linked to rheumatoid arthritis.