You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is RA is best diagnosed by? and explain in detail?
to establish diagnosis of rheumatoid ahritis are * Clinical criteria * ESR and CRP * Ultrasound or MRI * Rheumatoid factor and anti-citrullinated peptide antibodies DAVIDSON&;S 22nd EDITION;PAGE NO 1100