Laboratory tests for diagnosis of XXXX : advantages, disadvantages and future perspectives.

@entity2656 @entity1 @entity20687 @entity11884 @entity5419 @entity566 @entity112
Numerous biological tests point to the diagnosis of food sensitization: detection of specific @entity20687 by Rast techniques, multi-detection assays, immunoblotting, screening of basophil activation (BAT or FAST), assays for leukotriene LTC4 release (CAST), measurement of plasma @entity112 , serum tryptase, serum ECP, urinary EDN, completed by @entity2656 - @entity11884 test evaluating intestinal permeability, assay of fecal @entity20687 , Rast for specific IgG4. Primary screening for anti-food @entity20687 by multi-detection assays seeks justification from insufficient clinical data and false positive tests are common in @entity1 sensitized to pollens or latex, on account of in vitro cross reactivities (CR). Multiple CR explain positive Rast to vegetal food allergens in such @entity1 . Biological tests should not be performed as the first line of diagnosis. In vivo sensitisation is assessed by positive prick-tests, demonstrating the bivalence of allergens, as well as the affinity of specific @entity20687 , two conditions necessary to bridge membrane bound specific @entity20687 , leading to the release of mediators. Prick-tests are closer to clinical symptoms than biological tests. However, the diagnosis of @entity5419 is based on standardised oral challenges. Exceptions are high levels of specific @entity20687 to egg (> 6 kUl/l), peanut (> 15 kUl/l), fish (> 20 kUl/l) and milk (> 32 kUl/l), reaching a 95% predictive positive value. Rast inhibition tests are useful to identify masked allergens in foods. Research developments will have impact on the development of new diagnostic tools: allergen mixes reinforcing a food extract by associated recombinant major allergens, multiple combination of recombinant allergens (chips) or tests with synthetic epitopes aimed a the prediction of recovery. Laboratory tests take place in the decision free for the diagnosis for the @entity5419 and the follow-up of the levels specific @entity20687 is a tool to assess outcome and contributes to predict recovery or persistent @entity566 . Up to now the significance of positive laboratory tests showing the implication of @entity20687 is at the crossroads of the allergist's and biologist's expertise.
