Which description best matches the rheumatoid factor test characteristics?

Which description best matches the rheumatoid factor test characteristics?

• A. High specificity and high sensitivity
• B. High specificity and low sensitivity
• C. Low specificity and low sensitivity
• D. Low specificity and high sensitivity

Answer: (B)

Rheumatoid factor testing is best described as highly sensitive but not highly specific. In many people with rheumatoid arthritis, RF is positive, so the test will catch a large proportion of true RA cases (high sensitivity). However, RF can also be positive in a variety of other autoimmune diseases and even in some healthy individuals, especially older adults, which lowers specificity. So a positive RF supports RA in the right clinical setting but is not definitive, while a negative RF argues against RA more strongly in established disease but does not completely rule it out, since seronegative RA exists. The practical takeaway is that RF has high sensitivity and low specificity, which is why this description is the most appropriate.

Rheumatoid factor testing is best described as highly sensitive but not highly specific. In many people with rheumatoid arthritis, RF is positive, so the test will catch a large proportion of true RA cases (high sensitivity). However, RF can also be positive in a variety of other autoimmune diseases and even in some healthy individuals, especially older adults, which lowers specificity. So a positive RF supports RA in the right clinical setting but is not definitive, while a negative RF argues against RA more strongly in established disease but does not completely rule it out, since seronegative RA exists. The practical takeaway is that RF has high sensitivity and low specificity, which is why this description is the most appropriate.