rheumatoid factor-negative juvenile idiopathic arthritis (MONDO_0019432) can be described as follows. Rheumatoid factor-negative polyarthritis is a term used to describe a group of poorly defined heterogenous conditions that incorporates forms of rheumatoid factor-negative polyarthritis and forms of oligoarticular arthritis that become extensive in less than 6 months after onset. Also known as: juvenile rheumatoid factor-negative polyarthritis, polyarthritis without rheumatoid factor, rheumatoid factor-negative JIA.