Were you diagnosed with seronegative rheumatoid arthritis? First what does “seronegative” mean?

What is seronegative rheumatoid arthritis?

You have two labs your doc will run if he or she is suspicious or rheumatoid arthritis. Those labs are the RF and anti-CCP antibodies. Sufficienctly elevated levels of these antibodies confirm our history and physical exam findings and predict the aggressiveness of the disease.

I have inflammatory arthritic symptoms but my labs are negative

Ok, so you fit the bill for rheumatoid arthritis based on your clinicians analysis of your symptoms and all of the homework you’ve been doing on your own.

Occasionally, we run these labs and they come back negative. In this situation your provider may diagnose you with a seronegative rheumatoid arthritis. He or she may be right, but the issue here is that there are many rheumatoid arthritis mimics, which we have the better chance of teasing out with a positive RF and anti-CCP. A few of those include psoriatic arthritis, lupus, crystalline and infectious arthritidies.

A case of mistaken seronegative rheumatoid arthritis

A recent example included a woman who was diagnosed with rheumatoid arthritis and treated with methotrexate for several months. She noticed some improvement but decided to get a second opinion.

Her new providers ran some basic labs and noticed she had elevated liver enzymes, which may have explained some vague abdominal pain she had.

This was followed up with a more specific and deeper look at her liver and a gastroenterology referral.

What ended up happening was that she tested positive for Hepatitis C virus. What this woman needed was antivirals, not methotrexate. She was treated with Vosevi and all of her symptoms resolved.

Take home

Have you been diagnosed with seronegative RA? It’s a tricky thing, because many of the mimics may also respond to RA-specific treatments to some degree. But obviously methotrexate isn’t the best treatment.

All the more reason you want to be extra thorough if a rheumatoid picture looks present with absent antibodies.