What are the different blood tests?

Posted on: Wed, 04/05/2006 - 5:35am
Andrea L's picture
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Joined: 12/29/2005 - 09:00

My daughter's first allergist only ever did skin tests. The new allergist said blood tests are more accurate with food allergies and did a RAST test. This used a sclae of 1 to 6, I think. I've since heard of IgE and Elisa tests. I've heard of scales that go up into the 20's. Can someone help explain the different tests? The RAST test didn't seem very accurate to me. My daughter had a wide range, i.e 2-4 for wheat.

Posted on: Wed, 04/05/2006 - 1:16pm
Adele's picture
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Joined: 01/31/2005 - 09:00

I don't have any faith in the Elisa blood test. Right after I was dx with PA there was a local health fair that offered allergy testing. I assumed the blood testing was RAST but found out later it was ELISA.
Though it showed I was positive to peanuts, the ELISA showed I was negative to things that I know I am allergic to, such as cats, and positive to things that I'm not allergic to.
Later I spent some time on google researching the ELISA test and found out that it's not always regarded as a reliable test.

Posted on: Wed, 04/05/2006 - 11:51pm
jtolpin's picture
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Joined: 05/28/2003 - 09:00

2 tests that are used a LOT:
RAST -- Scores go from <.35 to >100 (and range from class 1-6)
Skin Prick Test: Big ole Lego block on your back, with allergens... the bigger the wheal (hive), the 'more allergic' you are.
False positives and negatives in both. NOT 100% accurate. Use as guideline.
Elisa? Dont know it. Avoid it IMO.
Jason
------------------
[b]* Obsessed * [/b]

Posted on: Thu, 04/06/2006 - 8:28am
McCobbre's picture
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Joined: 04/16/2005 - 09:00

I had an ImmunoCap blood test, which my doctor thinks is more accurate than a CapRast test.
However, I'll say that it turned back a negative to peanuts which I think I have (have reacted to and have tested positive on a skin prick test). It also turned back a positive to sesame which I was doubtful about at first but am confident about now and told me what I knew to be true about shellfish.
I wish I thought to have him include cats, because I think I'm off the charts there, and 4+ for skin prick (that I've always, always had for cats) probably doesn't begin to describe it.

Posted on: Thu, 04/06/2006 - 9:44am
maddiesmom's picture
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Joined: 12/20/1999 - 09:00

I would also like to know if anyone knows exactly what an IgG test is. I recently met someone who has children with allergies and she said she also had the allergist do an IgG test to test for "intolerances" to foods. My DD still gets digestive issues, even with all of her allergies out of her diet (and I have a very strict small comfort zone) Not sure if I should have this done for her to investigate any food she may be intolerant to, not just allergic to.
I did a search on the board and I couldn't find any topics on IgG tests. Anyone who know about this type of blood test..please fill me in.
Thanks! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]
Shandra

Posted on: Mon, 02/25/2008 - 10:16am
Kaviraj's picture
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Joined: 01/22/2008 - 18:46

Originally Posted By: jtolpin
Elisa? Dont know it. Avoid it IMO.
Jason
------------------
[b]* Obsessed * [/b]
Jason, if, as you admitted, you "don't know" anything about the LRA by ELISA/ACT Biotechnologies, then [b]why[/b] would your opinion be to avoid it? The test is very accurate (over 97% accurate per reactive item) and it measures delayed immunological reactions. Why would you encourage people to avoid a test that could help them?
I discussed the test [url="http://www.peanutallergy.com/boards/ubbthreads.php?ubb=showflat&Number=253799&PHPSESSID=26ad981b56dcc10b22d05f752a45a464#Post253799"]here[/url]
-- Pat

Posted on: Wed, 04/05/2006 - 1:16pm
Adele's picture
Offline
Joined: 01/31/2005 - 09:00

I don't have any faith in the Elisa blood test. Right after I was dx with PA there was a local health fair that offered allergy testing. I assumed the blood testing was RAST but found out later it was ELISA.
Though it showed I was positive to peanuts, the ELISA showed I was negative to things that I know I am allergic to, such as cats, and positive to things that I'm not allergic to.
Later I spent some time on google researching the ELISA test and found out that it's not always regarded as a reliable test.

Posted on: Wed, 04/05/2006 - 11:51pm
jtolpin's picture
Offline
Joined: 05/28/2003 - 09:00

2 tests that are used a LOT:
RAST -- Scores go from <.35 to >100 (and range from class 1-6)
Skin Prick Test: Big ole Lego block on your back, with allergens... the bigger the wheal (hive), the 'more allergic' you are.
False positives and negatives in both. NOT 100% accurate. Use as guideline.
Elisa? Dont know it. Avoid it IMO.
Jason
------------------
[b]* Obsessed * [/b]

Posted on: Thu, 04/06/2006 - 8:28am
McCobbre's picture
Offline
Joined: 04/16/2005 - 09:00

I had an ImmunoCap blood test, which my doctor thinks is more accurate than a CapRast test.
However, I'll say that it turned back a negative to peanuts which I think I have (have reacted to and have tested positive on a skin prick test). It also turned back a positive to sesame which I was doubtful about at first but am confident about now and told me what I knew to be true about shellfish.
I wish I thought to have him include cats, because I think I'm off the charts there, and 4+ for skin prick (that I've always, always had for cats) probably doesn't begin to describe it.

Posted on: Thu, 04/06/2006 - 9:44am
maddiesmom's picture
Offline
Joined: 12/20/1999 - 09:00

I would also like to know if anyone knows exactly what an IgG test is. I recently met someone who has children with allergies and she said she also had the allergist do an IgG test to test for "intolerances" to foods. My DD still gets digestive issues, even with all of her allergies out of her diet (and I have a very strict small comfort zone) Not sure if I should have this done for her to investigate any food she may be intolerant to, not just allergic to.
I did a search on the board and I couldn't find any topics on IgG tests. Anyone who know about this type of blood test..please fill me in.
Thanks! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]
Shandra

Posted on: Mon, 02/25/2008 - 10:16am
Kaviraj's picture
Offline
Joined: 01/22/2008 - 18:46

Originally Posted By: jtolpin
Elisa? Dont know it. Avoid it IMO.
Jason
------------------
[b]* Obsessed * [/b]
Jason, if, as you admitted, you "don't know" anything about the LRA by ELISA/ACT Biotechnologies, then [b]why[/b] would your opinion be to avoid it? The test is very accurate (over 97% accurate per reactive item) and it measures delayed immunological reactions. Why would you encourage people to avoid a test that could help them?
I discussed the test [url="http://www.peanutallergy.com/boards/ubbthreads.php?ubb=showflat&Number=253799&PHPSESSID=26ad981b56dcc10b22d05f752a45a464#Post253799"]here[/url]
-- Pat

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