Latex rast

my consultant thinks my asthma might be worked related and made worse by nasal upper airway problems, he thinks I might have allergies and that I might be allergic to latex so he told sent me to have some blood tests done for IGE, FBC and latex rast, anyone know what this is?

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I hope I have got this right:

FBC is full blood count

IgE is Immunogobulin E is an antibody the more you have the more allergic you are (note blood IgE can sometimes be very low when you are super allergic and somehow be stupidly high and you not show many symptoms)

RAST looks at the the IgE response in your blood to a specific thing in this case latex

Bex

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Hi bex

thanks for the info, and I hope you are well, just out of interest how reliable are these rast tests? what did your results say? cause i'm kinda hoping they find something soon so I don't have to have any more tests!

Lejaya

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You probably picked the wrong person so ask, my IgE is pretty high. I have not had rast to latex but house dust mite, birch and cat and some others are off the scale ie greater than 100, however I don't get sneezes, snuffles and watery eyes, so I am not the best example.

Bex

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usually they are pretty reliable, although I am the odd one out! Apparently some folk have low IgE and instead have IgG2, which acts in a similar way but isn't picked up on RAST testing - yep, that would be me!

It is likely that these will help work out what is going on.

S

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Owl -I'm wierd and odd too! Have low IGE but managed to have anaphylaxis (still can't spell) to skin prick testing!

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I have a friend with brittle asthma who doesn't post on here who has an IgE of 0.2 (stupid low) and yet gets anaphylaxis to milk and is so allergic to it that if she spills it over her hand she breaks out in blisters.

I have an IgE in the normal range (36 last time), but am fairly allergic - I get hayfever symptoms all year round, and the occasional generalised allergic reaction (not quite full blown anaphylaxis but urticaria, wheeze, lip swelling etc) to goodness knows what if I am not taking antihistamines and pred. I also react to virtually everything to varying degrees on skin prick testing. My RAST to HDM is high, but the others were normal when I had them done at RBH last year - and yet I know that I react to some of the things that they tested me for.

So serum IgE is certainly not the whole story. As well as the IgG2 thing, there's also a theory that serum (blood) IgE level can be markedly different from lung IgE - my friend mentioned above was tried on Xolair (after a real fight for funding) and seems to have had some response, and her consultant is theorising that the lung IgE issue is the reason why. I'm not aware that anyone actually measures lung IgE, though.

I also wonder about the actual mechanism of the test - apparently according to my hospital's lab it measures FREE IgE, ie that not actually bound to allergen. So potentially if you were allergic to something that you were being constantly exposed to, your IgE could all be bound up and would not be picked up in the test? Just my pet theory...

Anyway, I know one thing, and that is that I do not understand the whole shebang.

Em H

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how high does a Ige result have to be for a person to be allergic to something? also how low does the result have to be to be considered negative?