Investigation of suspected Giant Cell Arthritis (GCA) includes - Erythrocyte Sedimentation rate (ESR) Test measures the time in which red blood cells fall to the bottom of test tube. If red blood cells fall quickly to the bottom of test tube, it indicates inflammation. - C-Reactive Protein (CRP) Test which is formed by liver in response to inflammation. - Doppler Ultrasound generates images of blood flowing through blood vessels. - Magnetic Resonance Angiography (MRA) generates detailed images of blood vessels. - Position Emission Topography (PET) generates detailed images of major blood vessels such as aorta and highlight the sites of inflammation by radioactive substances. - Temporal Artery Biopsy (TAB) gives accurate diagnosis of Giant Cell Arthritis (GCA).