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Labs
Most of the tests people are given a target for don't have one, and that's the short form of this page. The longer form is that telling one disease from another and setting a goal number are two different jobs. Different studies answer them, and only one of the two has been answered here.
What the research found.
More than a third of people with rheumatoid arthritis had a normal result on at least one of three tests when first measured. The three were the sedimentation rate, C-reactive protein, and rheumatoid factor. Two large databases covered twenty-five years between them.
Almost a third of healthy people test positive for antinuclear antibodies at a 1 to 40 dilution, and the figure is 31.7 percent. At 1 to 320 it falls to 3.3 percent. So a positive result means very little without the dilution attached to it.
Anti-CCP is positive in 67 percent of people who have rheumatoid arthritis. It's negative in 95 percent of people who don't have it, so a positive result counts for a great deal. About a third of people with the disease test negative.
The 2024 Endocrine Society guideline looked for trials on routine vitamin D testing in healthy adults, and it found no such trial at all. It also found no clear evidence for a best blood level. So the target somebody gave you did not come from there.
Demay and colleagues, Journal of Clinical Endocrinology and Metabolism, 2024
In one adult population the HOMA-IR cut-off for insulin resistance ranged from 2.05 to 3.46. The only thing that changed was the math used to set it. The population under those two figures never changed at all, which is what makes the spread worth knowing about.
What these tests can and can't tell you
Blood tests in joint disease are useful, and they get asked to do a good deal more than they can. The most common error is reading a number as a verdict, when almost every test here moves the odds and very few settle anything on their own. Your joint exam counts for more than any single result, and so does your history, and so do your scans. There's a second point worth holding onto, which is that a test can be well studied for telling one disease from another without there being a number you should aim for.
A normal result doesn't mean nothing is wrong
This is the most useful fact on the page, and it's also the one that costs people the most. Two databases followed rheumatoid arthritis patients over twenty-five years, and more than a third had a normal result on at least one of three tests at the start, with both inflammatory markers normal in 33 to 42 percent. That holds where the stakes are higher too, and in one series of 130 people with giant cell arteritis, 23 had two normal markers. So if your tests are normal and your joints are swollen, say that plainly to whoever is looking at you, because swollen joints with normal blood still need a rheumatology review.
Where a target exists, and where it doesn't
Composite scores are the one place a target has strong trial support behind it, because trials treated people until the score reached a set level and got far more remission than usual care did. Accuracy figures are a different thing, and anti-CCP has good ones without having any number to aim at. Three tests are often given a target range, and not one of the three has one that holds up in joint disease, those being the omega-3 index, HOMA-IR, and vitamin D. Vitamin D is the one that counts most, because the only evidence-based figure is about bone health across a whole population and not a target for one person with joint disease.
Testing without a question
A test ordered with no question behind it gives a result you can't act on, and that isn't harmless. A positive antinuclear antibody in someone with no symptoms is the clearest case, because it causes real worry, gives no clear next step, and often leads to years of repeat tests. Researchers tested 825 healthy blood donors and two rheumatic diagnoses came out of it over five years of follow-up. Each test below has its own page saying what it measures, where its numbers came from, which people they came from, and what a result does and doesn't prove.
What to do this week.
Ask what question the test answers
A test ordered with no question behind it gives you a result you can't act on. Ask what would change depending on the answer, and ask before the blood is drawn.
Take a normal result back to the exam
If your tests are normal and your joints are swollen, say that plainly to whoever is looking at you. Swollen joints with normal blood still need a rheumatology review, whatever the paperwork looks like.
Ask where a target range came from
If you're handed a goal number for a single test, ask which study it came from and which people were in it. For the omega-3 index, HOMA-IR, and vitamin D there's no tested target in joint disease at all.
Take a mail-order panel to a clinician
These panels print a reference range beside every value, which makes anything outside it look like a finding. Take your results to somebody who can read them, and be ready to hear that a number doesn't need acting on.
Common misconceptions.
Myth. More labs is always better.
Reality. The point isn't to run every lab in existence. The point is to run the right small set, understand what they mean, and use them to track change. Eight well-chosen labs beats fifty random ones.
In plain words. The goal isn't more tests. It's the right few tests, understood well and tracked over time. Eight good ones beat fifty random ones.
Questions patients ask.
My markers are normal but I feel awful. Does that mean nothing is wrong?
No, and the research is clear on this. Two large databases followed people with rheumatoid arthritis, and more than a third had a normal result on at least one of three tests at the start, with both inflammatory markers normal in 33 to 42 percent. A normal result lowers the odds without ruling out joint disease. Your exam counts for more than the number does.
What number should I aim for on these tests?
For most of them there isn't one, and that's the most useful thing on this page. Composite scores do have targets, and trials back them up. Single tests like the omega-3 index, HOMA-IR, and vitamin D have no target tested in joint disease at all. If you were given a goal for one of those, it almost surely came from a different group of people and a different outcome.
Why doesn't a positive ANA mean I have lupus?
Because plenty of healthy people test positive, and how many depends entirely on the dilution used. At 1 to 40, almost a third of healthy people are positive, and at 1 to 320 it drops to 3.3 percent, so a result with no dilution attached is close to useless. Researchers screened 825 healthy blood donors and found two rheumatic diagnoses in five years.
Should I get a full autoimmune panel just to check?
Testing with no question behind it gives results you can't act on, and that isn't harmless. A positive antibody in a person with no symptoms causes real worry, gives no next step, and can lead to years of repeat tests chasing it. These tests earn their keep when a clinician has a specific question in mind, and ordered on spec they tend to cause confusion instead.
Do these numbers track how I'm doing over time?
Some do and many don't, and which is which varies from one test to the next. Inflammatory markers rise and fall with inflammation, and they feed the composite scores that guide treatment. Antibody levels like anti-CCP don't track disease activity well. So whether your own test is worth redoing is a fair question to put to whoever ordered it, and a reasonable one to ask twice.
Why is this page rechecking targets it used to print?
Because several of them didn't hold up. An earlier draft of this page printed eight target ranges with no source at all, and its vitamin D target was higher than the sufficiency level in the page's own reference. Each test now has its own page saying where its numbers came from. Where no tested target exists, the page says so rather than supplying one.
References.
- Sokka T; Pincus T. Erythrocyte sedimentation rate, C-reactive protein, or rheumatoid factor are normal at presentation in 35%-45% of patients with rheumatoid arthritis seen between 1980 and 2004: analyses from Finland and the United States. The Journal of rheumatology. 2009;36:1387-90. 10.3899/jrheum.080770Retrospective analysis of two consecutive usual-care RA databases
- Tan EM; Feltkamp TE; Smolen JS et al. Range of antinuclear antibodies in "healthy" individuals. Arthritis and rheumatism. 1997;40:1601-11. 10.1002/art.1780400909Multicentre cross-sectional study of a putatively normal population across 15 international laboratories
- Nishimura K; Sugiyama D; Kogata Y et al. Meta-analysis: diagnostic accuracy of anti-cyclic citrullinated peptide antibody and rheumatoid factor for rheumatoid arthritis. Annals of internal medicine. 2007;146:797-808. 10.7326/0003-4819-146-11-200706050-00008Diagnostic accuracy meta-analysis
- Demay MB; Pittas AG; Bikle DD et al. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline. The Journal of clinical endocrinology and metabolism. 2024;109:1907-1947. 10.1210/clinem/dgae290Society clinical practice guideline with GRADE methodology and commissioned systematic reviews
- Gayoso-Diz P; Otero-González A; Rodriguez-Alvarez M et al. Insulin resistance (HOMA-IR) cut-off values and the metabolic syndrome in a general adult population: effect of gender and age: EPIRCE cross-sectional study. BMC Endocrine Disorders. 2013;13. 10.1186/1472-6823-13-47Cross-sectional random population sample of 2
- Currier C; Bays A; Thomason J. Normal inflammatory markers in giant cell arteritis: a diagnostic blind spot. Rheumatology International. 2025;45. 10.1007/s00296-025-05930-3Retrospective diagnostic accuracy study within a single fast-track GCA clinic
- Hock E; Martyn-St James M; Wailoo A et al. Treat-to-Target Strategies in Rheumatoid Arthritis: a Systematic Review and Cost-Effectiveness Analysis. SN Comprehensive Clinical Medicine. 2021;3:838-854. 10.1007/s42399-021-00727-4Systematic review of randomised controlled trials
This page gathers the published research on this subject into one place. The studies behind it were published between 1989 and 2026, and every figure links to the paper it came from. Those studies were peer reviewed. This summary of them was not. Dr. Sarah Luebker is reviewing these pages one at a time and has not reached this one yet, so it carries no medical review date and nothing here is her opinion or her advice to you. Each page gets updated as she reaches it. It is here in the meantime because the science is worth having in one organized place that is easy to find and easy to read. Talk to your own clinician before acting on any of it.