What is all this blood work for?

Bit of a back story. I have chronic uveitis in both eyes. My right eye is worse. I've had 7 flair ups since February 2012. My ophthalmologist recommended I see a Rheumatologist because it's often caused by an auto immune disease. I saw her today and she ordered a bunch of tests. None of which I understand. The blood tests were HLA B27, ANA, RF, and Ace Angiotensin Conv Enz. She also ordered a chest X-Ray and a X-Ray of my Sacroiliac joint and my tailbone area because I am in constant pain there. She was instant on the chest X-Ray after I told her that I've had lower lobe pneumonia 3 times this year. Do any of these tests point to one specific thing she may be looking for, or is she just doing random tests?

Write Answer

Health Care

avatar
Jenivare
5 Answers
Contributor
5 people found this helpful

Disclaimer: I'm not a doctor. Here's [one paper that has them all](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832720/):

HLA-B27: Many antigens of the MHC, especially of HLA class I and II, have been associated with rheumatic disorders. HLA-B27 is present in approximately 90% - 95% of white patients with ankylosing spondylitis (chronic inflammatory disease of the axial skeleton with variable involvement of peripheral joints and nonarticular structures) and only 7% to 8% of the general population.

ANA: Immunologic studies that aid in the diagnosis of CSS\* include a CBC that reveals a peripheral eosinophila and the serologic presence of an ANA and a p-ANCA directed against MPO.

\*CSS: Churg-Strauss syndrome (CSS) is a necrotizing vasculitis affecting small and medium blood vessels characterized by eosinophilic infiltration, eosinophilic granulomas, nasal polyps, allergic rhinitis, conductive hearing loss, eye disease (scleritis, episcleritis, uveitis), asthma, fleeting infiltrates, alveolar hemorrhage, segmental necrotizing glomerulonephritis, heart failure, and vasculitic neuropathy. Initial symptoms typically suggest a reactive airway process similar to asthma.

RF: Rheumatoid Factor (RF) is helpful when evaluating patients who may have rheumatoid arthritis as the sensitivity is ~70% with a specificity of ~70%. Rheumatoid factor is absent in ~15% of patients with rheumatoid arthritis.

ACE: Laboratory investigations helpful in the diagnosis of sarcoidosis include a serum angiotensin converting enzyme (ACE) level and vitamin D levels. ACE levels are generally elevated, however, ACE levels lack disease specificity and therefore have limited diagnostic and therapeutic utility.

Any one of these separately doesn't have as much diagnostic power as all of them together. Basically it looks like a generalized for rheumatic diseases. The back x-ray is probably to check for the onset of ankylosing spondylitis. The lung x-ray is probably for sarcoidosis.

> Sarcoidosis is a systemic granulomatous disease characterized by noncaseating granulomas affecting multiple organ systems. The etiology of sarcoidosis is not known but believed to involve chronic inflammation.

> Imaging studies, in particular, chest x-ray or chest CT, show bilateral hilar lymphadenopathy and or interstitial infiltrates. Chest CT reveals nodular infiltrates that tend to be distributed along the bronchoalveolar structures.

Again, I'm not a doctor! I sure wish some mds would sign up for this subreddit though.

Was this answer helpful? Yes No
Contributor
5 people found this helpful

Hey, for not being a doctor, you're pretty spot on!

I'm a fourth year med student, but I'll just add on that if you're suspecting an autoimmune diseases, the symptoms usually overlap with a number of different diseases with different etiologies. Hence, you get an onslaught of different tests.

What's understood is that chronic uveitis is bad, and having so many flareups is worse. It hints that it's not just a random stroke of bad luck, but that you have something autoimmune brewing, and we have to find out what it is quick. So we do the panel of biomarkers and a chest xray because many autoimmune diseases have findings on xray as well, such as sarcoids or ankylosing spondylitis which is also associated with HLA-B27, but also Goodpasture's or Churg Strauss.

Edit: Obligatory thanks for the gold :)

Was this answer helpful? Yes No
Contributor
3 people found this helpful

Thank You both for answering my questions. I'm excited for the possibility of getting a diagnosis finally but scared to death of what that diagnosis may be. I've decided that if this doesn't work, my next step is going to be [The Ocular Immunology and Uveitis Foundation](http://www.uveitis.org)

Was this answer helpful? Yes No
Contributor
2 people found this helpful

I try not to answer stuff I know I don't know, but I'm not bad at looking up stuff and figuring out what it means. My daughter is in med school, and she sends me stuff to quiz her on, and sometimes teaches me a thing or two, so at least I'm comfortable enough with the terminology and basic ideas.

Was this answer helpful? Yes No
Contributor
2 people found this helpful

Yep I'd agree with the other posters for sure! Let us know what you find out :) fingers crossed!

If you have any pink or silver scaly skin lesions, let me know!

Was this answer helpful? Yes No
About HealthExamine
HealthExamine is a community dedicated to health care question and answers. The statements made on HealthExamine are not a substitute for medical care. If you have a medical emergency or your condition worsens, seek medical attention immediately.