In depth
Systemic sclerosis and blood tests
Two results do most of the work on this page, and both of them get repeated over the years. One is which antibody you have, and the other is what the tiny vessels at your nail base look like. Neither of the two tells you what happens next on its own.
What the research found.
One cohort of 1325 people with systemic sclerosis was sorted by antibody and by skin subset. The 374 with anticentromere antibodies and limited skin disease had the best outcomes of any group in it. Their 20-year survival was 65.3 percent, clinically significant lung fibrosis reached 8.5 percent, renal crisis 0.3 percent, and heart involvement 4.9 percent.
In that same cohort, anti-Scl-70 was associated with the highest rate of clinically significant lung fibrosis of any group. At 15 years it reached 86.1 percent in those with limited skin disease and 84 percent in those with diffuse skin disease. Those are the two largest figures on this page.
Nihtyanova and colleagues, Arthritis and Rheumatology, 2020
One nationwide Korean cohort reviewed 751 people with systemic sclerosis. Anti-Scl-70 was positive in 302 of them, or 42.5 percent, and anticentromere antibodies in 175, or 25.5 percent. Five-year survival was 94 percent and ten-year survival 87 percent.
One study looked at the nailfold vessels of 759 people with Raynaud's. A scleroderma pattern was found in 88 percent of those with systemic sclerosis. The absence of that scleroderma pattern had a negative predictive value of 88 percent, while positive predictive values were low.
One study compared how well each capillaroscopy measure separated systemic sclerosis from other causes of Raynaud's. Capillary loss did best, at an area under the curve of 0.905 from 0.869 to 0.942, with dilatation next at 0.863 and giants at 0.835. Micro-hemorrhages managed 0.720 and ramifications 0.604, which is close to useless.
Bournia and colleagues, Clinical and Experimental Rheumatology, 2020
One triage study followed 263 people referred to rheumatology for a positive antinuclear antibody. Only 24 percent turned out to have any antibody-associated rheumatic disease, and systemic sclerosis accounted for 2.3 percent, or 6 people. Another 26.2 percent of them had no evidence of any disease at all.
What the number means.
| Test | What it measures | How it performs in systemic sclerosis | What it can't do |
|---|---|---|---|
| Anticentromere antibody | One antibody that sorts people into a slower course | 374 carriers had 20-year survival of 65.3 percent and lung fibrosis in 8.5 percent | Predict one person's course. These are group rates over 20 years |
| Anti-Scl-70 | One antibody that sorts people toward lung fibrosis | Lung fibrosis in 86.1 percent with limited and 84 percent with diffuse skin disease at 15 years | Say when, or how severe. It sorts risk rather than timing it |
| Antinuclear antibody alone | A broad screening antibody found in many conditions and in well people | Of 263 people referred for a positive result, 2.3 percent had systemic sclerosis | Make a diagnosis. A quarter of those referred had no disease at all |
| Nailfold capillaroscopy, normal | A close-up look at the vessels at the nail base | Absence of a scleroderma pattern had a negative predictive value of 88 percent | Be relied on alone. It reassures better than it diagnoses |
| Capillary loss score | How many vessels are missing | Area under the curve 0.905, from 0.869 to 0.942, the best single measure | Replace the clinical picture. It separates groups rather than deciding cases |
| Ramification score | Branching vessels | Area under the curve 0.604, the weakest measure tested | Be used to rule anything in or out |
| Any disease activity index | A single number for how active the disease is | One review reports that no index is fully validated | Be quoted as settled, because no agreed index exists |
A reference range is not a target. Where a range on this page differs from the one your laboratory prints, the difference is explained above and sourced below. Where no trial has tested a target, this page says so rather than offering one.
Two results do most of the work
This disease is followed with a long list of tests, and two of them hold most of the information. One is a blood test and the other is a close look at your fingernails. Everything else on this page is detail arranged around those two results.
The blood test is which antibody you have, and the second is nailfold capillaroscopy. That one is a close-up look at the tiny vessels at the base of your nail, done in a clinic with a microscope. Neither of them takes long, and both of them get repeated over the years.
Neither predicts what happens to you, and that's the most important sentence on this page. Both sort you into a group whose rates over years are known, which is a different kind of information altogether. That distinction recurs through everything written below it, and it's easy to lose.
Which antibody you have
One cohort followed 1325 people with systemic sclerosis, sorting them by antibody and by how much skin was involved. Then it looked at what happened to each of those groups over twenty years. That's a long enough follow-up to see the differences between them properly.
The best group was clear, and it was the 374 people with anticentromere antibodies and limited skin disease. Their 20-year survival was 65.3 percent, clinically significant lung fibrosis reached 8.5 percent, renal crisis reached 0.3 percent, and heart involvement reached 4.9 percent. Those are the most reassuring figures anywhere on this page.
Anti-Scl-70 pointed the other way, and it pointed a good deal harder. Clinically significant lung fibrosis reached 86.1 percent in those with limited skin disease and 84 percent in those with diffuse skin disease, both at 15 years. That's a very large difference from the group described above.
It's worth reading those figures slowly, because they're easy to misread. They describe what happened to groups of people over fifteen and twenty years, and they don't say what happens to you. They don't say when either, and nothing anywhere on this page does.
How common each one is
One nationwide Korean cohort reviewed 751 people who had this disease. Anti-Scl-70 was positive in 302 of them, which is 42.5 percent, and anticentromere antibodies were positive in 175, which is 25.5 percent. So between them those two antibodies account for roughly two thirds of that whole cohort.
That cohort also reported overall survival, and it came out at 94 percent over five years and 87 percent over ten. Interstitial lung disease was the most common organ problem in it, at 52.7 percent of the group. Both of those figures describe one population at one point in its history.
Those two cohorts came from different countries and from different decades entirely. Reading them side by side is useful, and it isn't the same as pooling them into a single number. They have never been pooled, and this page isn't going to do it either.
A positive antinuclear antibody on its own
Many people reach a rheumatology clinic because one broad blood test came back positive. The test in question is the antinuclear antibody, which turns up in a great many conditions and in well people too. What happens to those people next is worth knowing before you get there yourself.
One study followed 263 people referred through a triage system for that very reason. Only 24 percent of them turned out to have an antibody-associated rheumatic disease of any kind, so three quarters did not. That's the headline, and the rest of the numbers fill it in behind.
Systemic sclerosis accounted for 2.3 percent of them, which is 6 people out of the 263. Lupus and Sjogren's accounted for 9.1 percent each, and 26.2 percent had no evidence of any disease at all. So the most common single outcome of that referral was nothing at all.
A positive result on that test is a reason to be seen rather than a diagnosis in itself. The numbers above are there so you can hold onto that. Waiting is a good deal easier when you know how often the answer turns out to be nothing at all.
The nailfold scan
One study looked at the nailfold vessels of 759 consecutive people who had Raynaud's. It sorted every result into one of three groups, which were normal, nonspecific, and showing a scleroderma pattern. That third group is the one this whole page is about.
That scleroderma pattern was present in 88 percent of the people with systemic sclerosis. It wasn't unique to them, because it also appeared in 71 percent with mixed connective tissue disease, 33 percent with Sjogren's, 17 percent with lupus, and 13 percent with rheumatoid arthritis. So the pattern points at the family rather than at one member of it.
The useful figure from that study is what a normal result rules out for you. The absence of a scleroderma pattern had a negative predictive value of 88 percent, while its positive predictive values were low. Those two numbers do different jobs, and only the first is strong.
So this test reassures a good deal better than it diagnoses. A normal scan is real reassurance, and an abnormal one starts a conversation rather than ending it there. Knowing which of those two you are holding changes what the next appointment is for.
Not all of the scan counts equally
One study compared each part of the scan against the others in the same patients. It asked which measure best separated systemic sclerosis from other causes of Raynaud's, and the answers weren't close. One of them does most of the work on its own.
Capillary loss did best, at an area under the curve of 0.905 from 0.869 to 0.942. Dilatation came next at 0.863, from 0.818 to 0.907, and giant capillaries reached 0.835, from 0.787 to 0.884. Those three are the ones doing real work in a scan.
Two of the measures did a good deal worse than those three. Micro-hemorrhages reached 0.720, from 0.662 to 0.779, and branching vessels reached 0.604, from 0.539 to 0.670. Those two are the ones worth discounting when somebody quotes a scan at you.
Here is how to read all of those numbers at once. A perfect test scores 1.0 and a useless one scores 0.5, so capillary loss is doing real work and branching vessels are barely doing any. That scale is worth remembering, because areas under the curve turn up everywhere in medicine.
What the scan can and can't predict
Two studies asked whether the nailfold scan points forward as well as describing the present moment. Both of the two found that it does. Both also did it on very few people, and the numbers on this page show that clearly enough.
One followed 34 people with early disease for 3 years, and eight of them went on to develop definite systemic sclerosis. An active or late pattern at the start predicted that, at an odds ratio of 30.0. That number looks enormous until you read the interval that comes with it.
The interval on that odds ratio ranges from 2.1 to 421.1. An interval spanning two orders of magnitude is what 8 events in 34 people produces, and it means the size of the effect is unknown. The direction of the finding is real and the size of it is not established.
A second study of 86 people found a late pattern predicting digital ulcers at an odds ratio of 6.03, from 1.52 to 23.86. The same caution applies to it, because the direction holds up and the size does not. Read the interval before the number in both of those cases.
What no test here measures
One review asked whether any single index captures how active this disease is, and its answer was a short one. No fully validated index exists anywhere in the published literature. That's a real absence in the literature rather than something missing from what this site holds.
It compared four of those indices against what happened over the next three years. All three main indices correlated with lung involvement, and all three tracked forced vital capacity, carbon monoxide transfer, skin score, and capillaroscopy scoring. So those indices are measuring something real, which is worth saying.
Not one of them has been settled on as the measure, which is the part that counts. That means activity in this disease gets judged rather than read off a number, and a team that knows you is doing the judging. It's a slower answer than a score would be, and it's the one available.
That's worth knowing before somebody quotes you a score for your own disease activity. Ask what the score is, ask what it was validated against, and ask what your team does with it. Those three questions between them settle how much weight a score deserves.
Common misconceptions.
Myth. A positive antinuclear antibody means I have scleroderma.
Reality. It usually means something else entirely, and one study puts numbers on that. It followed 263 people referred to rheumatology for a positive result, and only 24 percent had any antibody-associated rheumatic disease. Systemic sclerosis accounted for 2.3 percent, which is 6 people, and another 26.2 percent had no evidence of any disease at all. So the broad test is a reason to look further and nothing more.
Myth. My antibody tells me what will happen to me.
Reality. It sorts you into a group with a known rate, which isn't a prediction about you. In one cohort of 1325 people, those with anticentromere antibodies had lung fibrosis in 8.5 percent and those with anti-Scl-70 in 84 percent or more at 15 years. Those are group rates over fifteen and twenty years, and they don't say what happens to you or when.
Myth. An abnormal nailfold scan means the disease is progressing.
Reality. It raises the odds and it doesn't settle them. One study followed 34 people with early disease for 3 years, and 8 of them progressed to definite systemic sclerosis. An active or late pattern at the start predicted that, at an odds ratio of 30.0, and the interval ranges from 2.1 to 421.1. That width is what 8 events in 34 people produces, so read the interval rather than the number.
Myth. All the capillaroscopy measures count the same.
Reality. They don't count the same, and one study ranked them against each other. Capillary loss separated the groups best, at an area under the curve of 0.905 from 0.869 to 0.942, with dilatation at 0.863 and giants at 0.835. Micro-hemorrhages managed 0.720 and branching vessels 0.604. A test scoring 0.5 is no better than a coin toss, so the last of those is close to useless on its own.
Myth. There must be a score that says how active my disease is.
Reality. There isn't a fully validated one, and a review says so directly. It compared four candidate indices against what happened over three years, and all three main indices tracked lung involvement. They also correlated with lung function, skin score, and capillaroscopy scoring, and not one of the four has been settled on. So your team judges activity rather than reading it off a number.
Cautions specific to this condition.
- Ask which antibody you have, because it's the single result that sorts the rest. The two most common in one Korean cohort of 751 people were anti-Scl-70 at 42.5 percent and anticentromere at 25.5 percent.
- Read a group rate as a group rate. A figure of 8.5 percent over 20 years describes 374 people, not your next appointment.
- Take a normal nailfold scan as reassurance and an abnormal one as a reason to keep looking. Its negative predictive value was 88 percent and its positive predictive values were low.
- Watch the width of an interval before the size of an odds ratio. One on this page ranges from 2.1 to 421.1 and rests on 8 events.
- Expect no single number for how active your disease is. No index is fully validated, so this gets judged rather than measured.
- A positive antinuclear antibody on its own settles nothing. In one study a quarter of people referred for it had no disease at all.
Discuss any change with the rheumatologist who manages your care. Nothing here replaces that conversation.
Questions patients ask.
Which blood test holds the most information here?
The answer is which antibody you have, and in one cohort of 1325 people it sorted outcomes more sharply than anything else measured. Those with anticentromere antibodies and limited skin disease had 20-year survival of 65.3 percent and lung fibrosis in 8.5 percent. Those with anti-Scl-70 had lung fibrosis in 84 percent or more at 15 years. Ask your team which of the two is yours.
What does anti-Scl-70 mean for me?
It puts you in the group with the highest rate of lung fibrosis. In that cohort the figure was 86.1 percent with limited skin disease and 84 percent with diffuse skin disease, both at 15 years. In one Korean cohort of 751 people it was the most common antibody, at 42.5 percent. It sorts risk rather than predicting the course you personally will take.
Is a positive antinuclear antibody enough to diagnose this?
No, and the numbers behind that answer are striking. One study followed 263 people referred to rheumatology for a positive result, and only 24 percent had any antibody-associated rheumatic disease at all. Six of them, or 2.3 percent, had systemic sclerosis, more than a quarter had no evidence of disease, and the test is a starting point rather than an answer.
What does the nailfold scan add?
It looks at the tiny vessels at the base of your nail, and one study did it in 759 people with Raynaud's. A scleroderma pattern was present in 88 percent of those with systemic sclerosis. The absence of that pattern had a negative predictive value of 88 percent, while its positive predictive values were low. So a normal scan reassures more than an abnormal one decides.
Which part of the scan counts most?
Capillary loss, on the one study that ranked them against each other. It reached an area under the curve of 0.905, from 0.869 to 0.942, with dilatation next at 0.863 and giant capillaries at 0.835. Micro-hemorrhages reached 0.720 and branching vessels 0.604. A perfect test scores 1.0 and a useless one 0.5, so that last measure holds very little on its own.
Can the scan predict what happens next?
It points, and it points loosely rather than sharply. One study followed 34 people with early disease for 3 years and 8 developed definite systemic sclerosis, at an odds ratio of 30.0 from 2.1 to 421.1. Another found a late pattern predicting digital ulcers at 6.03, from 1.52 to 23.86. Both of those intervals are very wide, so read them before the numbers.
Is there a single score for how active my disease is?
No fully validated one exists, and a review that compared four of them says so. All three main indices tracked lung involvement over three years, and they also correlated with lung function, skin score, and capillaroscopy scoring. So they measure something real, and no one of them has been settled on. That means activity gets judged by your team rather than read off a number.
References.
- Nihtyanova SI; Sari A; Harvey JC et al. Using Autoantibodies and Cutaneous Subset to Develop Outcome-Based Disease Classification in Systemic Sclerosis. Arthritis Rheumatol. 2020;72:465-476. 10.1002/art.41153Journal Article
- Moon KW; Lee SS; Lee YJ et al. Clinical and Laboratory Characteristics and Mortality in Korean Patients with Systemic Sclerosis: A Nationwide Multicenter Retrospective Cohort Study. J Rheumatol. 2018;45:1281-1288. 10.3899/jrheum.171443Journal Article
- van Roon AM; Huisman CC; van Roon AM et al. Abnormal Nailfold Capillaroscopy Is Common in Patients with Connective Tissue Disease and Associated with Abnormal Pulmonary Function Tests. J Rheumatol. 2019;46:1109-1116. 10.3899/jrheum.180615Journal Article
- Bournia VK; Kottas K; Panopoulos S et al. Differential performance of nailfold video capillaroscopic parameters in the diagnosis and prognosis of systemic sclerosis. Clin Exp Rheumatol. 2020;38 Suppl 125:29-39. PMID 31969216Cross-sectional diagnostic study with follow-up
- Fitch-Rogalsky C; Steber W; Mahler M et al. Clinical and Serological Features of Patients Referred through a Rheumatology Triage System because of Positive Antinuclear Antibodies. PLoS ONE. 2014;9:e93812. 10.1371/journal.pone.0093812Cross-sectional retrospective analysis of a central rheumatology triage database
- Zumstein Camargo C; Kayser C. Capillaroscopy changes are associated with disease progression in patients with early systemic sclerosis: A prospective study. Int J Rheum Dis. 2019;22:1319-1326. 10.1111/1756-185X.13592Prospective study of 44 patients with early systemic sclerosis by LeRoy and Medsger 2001 criteria
- Martins A; Pimenta S; Oliveira D et al. Can microvascular damage predict disease severity in patients with systemic sclerosis?. Reumatol Clin (Engl Ed). 2024;20:366-371. 10.1016/j.reumae.2024.07.006Retrospective study of 86 patients with systemic sclerosis who had nailfold videocapillaroscopy within 6 months of diagnosis
- Groseanu L; Petrescu S; Balanescu A et al. Do We Have Good Activity Indices in Systemic Sclerosis?. Curr Rheumatol Rev. 2022;18:39-47. 10.2174/1573397117666210913102759Study of 91 systemic sclerosis patients comparing four disease activity indices against subsequent organ damage over three years: the European Systemic Sclerosis Study Group activity index
- Boulon C; Aiouaz S; Blaise S et al. Correlation between capillaroscopic classifications and severity in systemic sclerosis: results from SCLEROCAP study at inclusion. Clin Exp Rheumatol. 2019;37 Suppl 119:63-68. PMID 31172926Multicentre prospective study
- Alcala-Gonzalez LG; Guillen-Del-Castillo A; Aguilar A et al. Oesophageal dysmotility patterns are associated with distinct clinical phenotypes and prognosis in patients with systemic sclerosis. Rheumatology (Oxford). 2025;64:6250-6258. 10.1093/rheumatology/keaf433Cohort of 201 patients with systemic sclerosis
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.
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