6 posts in this topic

I am a little confused about the SCL-70. My latest labs show my SCL-70 AB levels at 4.7.


The one before that was 6.5.


My doctor (and the lab reports) say that's positive.


However, I was reading some other posts and it seems that some people are saying their levels are in the hundreds. Am I misinterpreting this or reading it wrong?


I've looked all over for some sort of reference as to the ranges, but no luck.


Also, does it mean anything that my levels have gone down since the last blood test?


I got my lab results back but have to wait almost two weeks until my next appt with the rheumatologist?





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Hi Lisa,


Welcome to Sclero Forums! I'm sure glad you found us. As it happens, every lab is different when it comes to Scl-70 tests, so you need to rely on what your lab claims is positive.


To the best of my knowledge, it means next to nothing any change in Scl-70 levels; in other words, it is not necessarily related to any increased activity of the disease or symptoms. But please keep in mind that I have no medical training at all and if someone else has better input or sources, we'll go with that. The Scl-70 is most helpful for diagnosis and classification of scleroderma, when considered in light of a constellation of symptoms.

Warm Hugs,


Shelley Ensz

Founder and President

International Scleroderma Network (ISN)

Hotline and Donations: 1-800-564-7099


The most important thing in the world to know about scleroderma is sclero.org.

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Hi Lisa,


My first 2 tests were from a lab with reference ranges <1 = negative


My last test was at a lab that showed <20 were negative


I have also seen tests that say <100 = negative


It all depends on what test your lab uses, you need to refer to that particular lab's reference range. Can you go back to the lab and sign a release to get your results?


Sorry, I know this is clear as mud :(


Hang in there sweetie, waiting is so hard and I have done alot of that in the last year but I survived, know you will too :)





Diffuse Scleroderma Diagnosed March 2009

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Hi Lisa,


I'm just chiming in with a welcome and a hug. OK, and a reminder that diagnosis isn't made on the basis of antibodies alone. There are a lot of other things a doctor should look for as well. In the section on Diagnosis, there is more information on that. The same goes for various markers of disease progression or lack thereof.


Did you know that scleroderma is a test in and of itself? Sure is, a test of our sense of humour! :lol: You definitely want to be in the positive range on this one.


Warm wishes and a warm welcome,

Jeannie McClelland

(Retired) ISN Director of Support Services

(Retired) ISN Sclero Forums Manager

(Retired) ISN Blog Manager

(Retired) ISN Assistant News Guide

(Retired) ISN Artist

International Scleroderma Network

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Hi Lisa.


Just in case interpretation of ANA tests were not sufficiently confusing (false positives, etc.), the labs use two different methods for expressing the results.


The first is the titer method, which is expressed as a ratio and indicates the number of times the blood sample must be diluted before no anti-nuclear antibodies can be detected. The second number in the ratio starts with 40 and then doubles (40, 80, 160, 320, etc.). For example, a titer of 1:40 means forty dilutions are required. With the titer method, a result of 1:40 or 1:80 (i.e., anything less than 100) is generally regarded as negative.


The other method (not sure what it's called) expresses the result as an absolute number. It sounds as though that's the method used by the lab that evaluated your tests. So, the "less than 100" rule would not apply in your case.


I hope your rheumatologist will be able to help in explaining your numbers.

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I belive there is two different kits or ways to test for SCL-70. One kit produces numbers such as 6.5 where 1.0 and anything above is positive. Another method produces numbers in the hundreds and I believe everything above 120 is positive. Hope that helps, and hope I remembered this correctly.

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