[KarolH]

Hi my fellow Lupies,

I am reading a lot lately and trying to gain more knowledge since my new dx of Lupus and APS.

I keep coming across the Anti Sm testing and it mentions that RNP is part of Anti Sm..............so needless to say I am confused.

I have gone to links here on the board about blood work to try and gain a better understanding of this and I am still confused.

IN LAYMAN'S TERMS..............can someone help me understand this.:wink2:

 

[Lily]

Hi Karol,

They are two different antibodies. They are 2 of the 5 antibodies tested for under the test called ENA (Extractable Nuclear antigen antibodies). The other 3 are Ro (SS-A), La (SS-B) and Scl 70.

love
Lily

 

[cath]

HI Karol,

No they are not the same, not even subsets of the same family.

Anti Sm (sm stands for smith) is quite specific for lupus.

Anti RNP is seen in lupus and in MCTD.

Which sources were you reading that said they are the same? It can be tricky sifting through fact and fiction sometimes, especially with info on the web. In general sites published by academic centers, professional journals or large hospitals are more reliable than fourm discussions or lay support groups.

As one member very accurately and ammusingly said - avoid anything in pretty colours or with lots of pictures:wink2::blush::wink2:

X C X

 

[Clare.T]

To compare them further:

Diagnostic value

Anti- Sm is specific for lupus assuming other test results, symptoms and health history support an SLE diagnosis. 20%-30% of people with lupus have these antibodies It is more common in blacks than whites and might be associated with a greater incidence of nephritis ( kidney) disease.

Anti- RNP is important diagnostically for distinguishing autoimmune connective tissue disease from other possible causes of similar symptoms. Its significance also depends on what other symptoms etc there are. It is not specific to lupus, it is found in SLE 20%-30% and in a few people with scleroderma and rheumatoid arthritis.

If high levels of anti RNP are being regarded as a criterion for an MCTD diagnosis then of course 100% of those with an MCTD diagnosis will have a high anti RNP result. It all depends on which set of diagnostic criteria is being used and depends too on other test results and symptoms

If there is an overall compelling syndrome ( set of symptoms) strongly suggestive of MCTD but anti- RNP isn't being regarded as a formal requirement then some 67% with MCTD type symptoms will have anti- RNP.

There are different types of anti RNP but we rarely hear of them. It is suggested that some of them might have more specific disease/ symptom associations or might predict future developments and prognosis but as things are, the disease you have is the symptoms you have got, whatever the disease is being called. It's impossible to say how it will develop.



Clare

 

[KarolH]

high levels of anti RNP

First of all thank you ALL for your replies.

So, what constitutes a high RNP?

What is a normal RNP?

 

[Lily]

Hi Karol,

Never being positive on this I am not sure. I have a feeling that any reading showing is positive, but have no idea what is classed as a high reading. Perhaps start a seperate post asking those who do have the antibody.

love
Lily

 

[KarolH]

Thanks Lily, I will.:wink2:

 

[Clare.T]

Somewhere it mentions what 'normal', 'equivocal' and 'above normal are, according to one reference range

If it isn't easy to find, surely we can assume that it doesn't matter, so why worry? Labs often give some comment about a test result such as, "RNP* = indicates a CTD" or a list of diseases in which it is found.

After that, it is up to the doctor to make what he wills of it

Clare

 

[KarolH]

So true Clare.

When I ask questions it is generally always for my knowledge and really not because I worry.

I am not one to worry.

My favorite saying, "It is what it is"!

I take life in strides and do not worry about what I can't change.

I hope you have a great weekend and thanks for all the support and knowledge.:wink2::wink2::wink2:

 

[Maia]

Here's a link to a website I've used for information on various blood tests. It gives ranges as well as an explanation of significance. You can find just about any blood test on this site and some ranges... this link takes you right to the RNP antibody one though.

http://www.medicine.uiowa.edu/Path_Handbook/handbook/test1674.html

 

[KarolH]

As always, thanks so much Maja.:wink2: