Placing a sign on the O.R. door indicating that the patient is allergic to latex is a good idea. Remind the surgical service of these precautions. Always be prepared to treat. See Diagnosis of Anaphylaxis . Onset is generally 20 - 60 minutes after exposure to the antigen.
Hypotension is the commonest sign.
A rash is not always seen. Serum mast cell tryptase levels are high during an episode and up to 4 hours after. Take blood in an EDTA tube. These tests will help confirm the diagnosis of anaphylaxis, but do not identify latex as the antigen. Results will not be immediately available.