Enquire about risk factors, and allergic symptoms that occur after contact with latex-containing items.
Ask specifically about:
Pre-operative testing should only be undertaken if risk factors or allergic symptoms are present. Testing requires referral to an allergist.
The RAST test is an in vitro test for IgE antibody directed towards latex. It is quite specific for latex allergy, but its variable sensitivity( 65 - 85%), and cost, make it less useful as a screening test.
This involves dropping latex antigen in solution onto skin and pricking the skin gently with a needle through the solution. The latex-allergic patient exhibits a wheal-and-flare reaction. There is a very small but definite risk of anaphylaxis. The latex proteins that are responsible for allergy are still being investigated and a standardised, FDA-approved, latex extract with which to perform the test is not yet available.
Intradermal testing is similar to skin-prick testing but the antigen is injected intradermally. This method is more sensitive than SPT but carries a larger risk of systemic reaction because the antigen cannot be wiped from the skin.
Bronchial challenge testing is employed in some centres but is controversial.
NOTE that if your patient has had an intra-operative allergic reaction, testing has to be delayed. Mediators have been depleted and testing may produce false negative results.