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2018

ANUÁRIO DO HOSPITAL DONA ESTEFÂNIA
REPOSITÓRIO MÉDICO CIENTÍFICO

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FX5: IS IT REALLY WORTH ASKING FOR?

Cátia Alves1, Ana Margarida Romeira1, Vitória Matos2, Paula Leiria Pinto1

1- Serviço de Imunoalergologia, Hospital de Dona Estefânia, Centro Hospitalar de Lisboa Central, EPE, Lisboa
2- Serviço de Patologia Clínica, Hospital de São José, Centro Hospitalar de Lisboa Central, EPE, Lisboa

- XXXVI European Academy of Allergology Clinical Immunology, Helsínquia, 17-21 Junho 2017
- Apresentação como poster; publicação de resumo
- Reunião Internacional

Resumo:
Introduction: Fx5, a food mixture of milk, egg white, fish, peanut, wheat and soybean, is largely used for food allergy detection. Besides the fact that it is questionable if this is the better approach to identify a food allergy, the information that the test provides may represent a pitfall because a positive or negative result does not mean food allergy presence or absence, respectively.
Objective: The goal of our study was to access the reason for fx5 request in a Pediatric Hospital and to analyze its suitability.
Methods: The fx5 requests, performed in a pediatric population of D. Estefânia Hospital over a five months’ period, were analyzed, concerning demographic data, reason for request and attitude taken due to the result.
Results: A total of 128 results were accessed (each one corresponding to one children). Of these 128 children, 75 (58,6%) were male, with an age range of 1 month to 18 years old (average 5,4; SD ± 3,92). This test was requested due to respiratory symptoms in 37 patients, gastrointestinal symptoms in 23 patients, cutaneous symptoms in 20 patients and nonspecific complaints in 48 patients. All of these symptoms were not directly related with food intake. A positive result was obtained in 25 patients; of those, only 15 were referenced to our Immunoallergology Department. In all of them a detailed clinical history was obtained and diagnostic tests (skin prick tests and specific IgE) were performed in the ones considered suitable. Food allergy was diagnosed in only one patient.
Discussion: In the vast majority of patients, fx5 was asked for nonspecific complaints and often without a clinical history suggestive of food allergy. Moreover, a positive fx5 test does not mean clinical reactivity or food allergy. On the other hand, the clinical history allows us to identify a suspect trigger in most of the children with food allergy. In such cases, it is preferable to request the specific IgE towards the allergen, which gives a more precise and accurate result, instead of the fx5. As our results showed, in the majority of the cases, the fx5 request was often made without complying with a reasonable criterion, implying unnecessary costs. The high number of requests verified may be explained because it is an easily accessible analysis but this attitude should be discouraged.

Palavras Chave: Fx5; food allergy;