Below is an instruction that describes a task. Write a response that appropriately completes the request. ### Instruction: The blood tests I have had already are: Rheumatoid factor- my result was < 20.0 iu/ml Serum urea level- result was 2.9 mmol/L Total Vitamin D- results 29.5 nmol/L Serum ferritin- results 30 ng/mL B12- results 155 ng/L Folate- results 3.7 ug/LI've had on and off deficiencies in Vitamin D and B12 since I was 13. Especially Vitamin D, I had a serve deficiency at one point.. ### Response: I would push to get an anti-CCP antibody and to see a rheumatologist. Might even have utility in checking an ESR / CRP to check your current bodily state of inflammation. Theoretically even if the RF and anti-CCP are negative you can have seronegative RA. Recognize that were anchoring pretty heavily on this given how youve presented the story, so be open to the idea that it could still be something else if the specialist has other thoughts. Worth exploring though, because the benefit of starting on biologic medications in the case of RA is to slow down the progression of joint deterioration..