<prompt> A 45 year old female presents with the complaint of pain in the metacarpophalangeal, proximal interphalangeal and metatarsophalangeal joints of both right and left hands. Serology showed positive anti-CCP antibodies. She was placed on infliximab for control. Which of the following need to tested before starting treatment?Complete blood countUric acidG6PDPPD skin test  <response>: Answer: d PPD skin test The patient is having rheumatoid arthritis which is diagnosed by the positive anti-CCP levels on serology. Biological disease modifying anti rheumatoid drugs include following TNF a inhibitors: Infliximab, Etanercept, Adalimumab, Golimumab Infliximab is chimeric monoclonal antibody while Adalimumab Golimumab are human monoclonal antibodies. Anti TNF agents are to be avoided in active infections and hypersensitivity reactions. There is an increased risk of opportunistic infections and flare up of latent tuberculosis. Hence obtaining a purified PPD skin test is a mandatory requirement for starting TNF a inhibitors. 