26th May 2025

A 58-year-old female presents with a few weeks’ history of bilateral painful knees, which are worse when going up the stairs or after activity.

A 58-year-old female presents with a few weeks’ history of bilateral painful knees, which are worse when going up the stairs or after activity. She often feels like her knee is ‘giving way’ and can feel a grating sensation when moving the joint. She has noted swelling over both knees and stiffness in the morning, although she admits this does not last for longer than a few minutes. She has no significant past medical history, but her mother had rheumatoid arthritis. On examination, she has bilaterally swollen knees, which are not erythematous or warm to touch. Range of movement is limited in both knees.

Which of the following investigation results would you be least likely to see in this patient?

Select the SINGLE most appropriate option from the list below. Select ONE option only.