Is molecular allergology cost-effective and cost saving in children with suspected peanut allergy compared to double blind placebo controlled food challenge (DBPCFC), open oral food challenge and skin prick test in Sweden?

Proyecto VALIDA: Validation of ALlergy In vitro Diagnostics Assays (Herramientas y recomendaciones para la valoración de las pruebas in vitro en el diagnóstico de la alergia)

En la evaluación del paciente con sospecha de alergia las pruebas de detección y cuantificación de la inmunoglobulina E (IgE) específica in vitro se usan de manera habitual en los laboratorios clínicos para ayudar en el diagnóstico de la alergia. Actualmente existen diferentes alternativas comerciales para realizar estos ensayos, pero los resultados obtenidos por cada uno de ellos pueden variar, lo que condiciona el diagnóstico y el tratamiento que se le proporcionará al paciente. Con el fin de dar respuesta a los retos planteados por las diferencias entre las distintas técnicas para la determinación in vitro de la IgE específica, un grupo de expertos ha recogido en un documento una serie de recomendaciones sobre las implicaciones que puede tener el uso de una determinada técnica in vitro y el impacto en el manejo del paciente alérgico que suponen las diferencias entre las distintas técnicas. La lectura y el análisis de este documento de consenso ayudarán a entender las implicaciones que tiene el cambio de método de diagnóstico in vitro en el manejo del paciente con alergia, en su calidad de vida y en los costes socioeconómicos asociados a la enfermedad.

VALIDA project: Validation of allergy in vitro diagnostics assays (Tools and recommendations for the assessment of in vitro tests in the diagnosis of allergy)

In vitro allergen-specific immunoglobulin E (IgE) detection and quantification tests are routinely performed in clinical laboratories to diagnose patients with a suspected allergy. Numerous commercial assays are available to test for allergies, but the results can vary widely, thereby influencing both diagnosis and treatment. Given the challenges posed by differences in the various assays for in vitro determination of specific IgE, a group of experts has compiled in a document a series of recommendations on the implications that the use of a certain in vitro technique may have and the impact on the management of the allergic patient that the differences between the various techniques represent. The reading and analysis of this consensus document will help to understand the implications of the change of in vitro diagnostic method in the management of the patient with allergy, in the quality of life and in the socioeconomic costs associated with the disease.

A Retrospective Clinical Audit of the ImmunoCAP ISAC 112 for Multiplex Allergen Testing

INTRODUCTION

Complex cases of multiple allergies can be particularly difficult to diagnose using standard methods such as skin prick tests and assessment of a patient's allergic history. Multiplex allergy testing may improve outcomes for allergy patients by avoiding misdiagnosis and providing reassurance. The ImmunoCAP Immuno Solid-Phase Allergen Chip (ISAC) 112 is a CE-marked, molecular, multiplex, allergy test that can test for IgE antibodies to 112 components from 51 allergen sources. However, its clinical utility is unknown and is difficult to estimate due to the complexity of the diagnostic pathway in which it is used.

OBJECTIVE

To assess how the ImmunoCAP ISAC 112 is currently being used in UK practice. The patient populations in which it may have the most benefit were examined, and the sequence of other tests implemented alongside ISAC was determined.

METHODS

A retrospective audit of 100 patient cases from 2 UK tertiary allergy clinics was performed. Fifty paediatric and fifty adult cases were selected for audit. The indications for ordering an ISAC test, the other tests used alongside ISAC, and changes in management actioned by the ISAC test were investigated.

RESULTS

73.6% of paediatric and 78% of adult patients referred for an ISAC test were suspected to have multiple sensitizations. The sequence of testing varied greatly between cases, but 70% of adult and 98% of paediatric patients had at least one other investigation prior to an ISAC test. In most cases, ISAC testing confirmed clinical suspicion.

CONCLUSIONS

A prospective research study is necessary to further investigate the clinical utility and cost-effectiveness of the ISAC. A UK national registry would be of great benefit but will require a large resource base.

ImmunoCAP® ISAC and Microtest for multiplex allergen testing in people with difficult to manage allergic disease: a systematic review and cost analysis

BACKGROUND

Allergy is a form of immune-mediated exaggerated sensitivity (hypersensitivity) to a substance that is either inhaled, swallowed, injected or comes into contact with the skin. Foreign substances that provoke allergies are called allergens. It has been claimed that multiplex allergen testing may help in diagnosing the cause of symptoms in patients with an unclear cause of allergy or who are allergic to more than one substance.

OBJECTIVES

To evaluate multiplex allergen testing [devices that can measure the presence of multiple immunoglobulin E (IgE) antibodies in a patient's blood at the same time], by assessing (1) clinical effectiveness (allergy symptoms, incidence of acute exacerbations, mortality, adverse events of testing and treatment, health-care presentations or admissions, health-related quality of life); (2) effects on treatment (diet, immunotherapy medications, other potential testing); (3) any additional diagnostic information provided by multiplex allergen testing; and (4) cost-effectiveness (cost of different assessment strategies).

METHODS

Fifteen databases were searched from 2005 to April 2015, including MEDLINE (via OvidSp), MEDLINE In-Process Citations, MEDLINE Daily Update, PubMed (National Library of Medicine), EMBASE, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment (HTA) database, Science Citation Index (SCI), Conference Proceedings Citation Index-Science (CPCI-S), BIOSIS Previews, Latin American and Caribbean Health Sciences Literature (LILACS), National Institute for Health Research (NIHR) HTA programme, and the US Food and Drug Administration (FDA); supplementary searches of conference proceedings and trials registries were performed. Review methods followed published guidance from the Cochrane Collaboration and the Centre for Reviews and Dissemination, University of York, UK. The methodological quality of included studies was assessed using appropriate published tools or a review-specific tool designed by the project team. Studies were summarised in a narrative synthesis. Owing to a lack of data on the clinical effectiveness of multiplex allergen testing, no long-term cost-effectiveness model was developed. A conceptual model structure was developed and cost analyses were performed to examine the short-term costs of various possible diagnostic pathways.

RESULTS

Fifteen studies were included in the review. The very limited available data indicated that the addition of multiplex allergen testing [ImmunoCAP(®) Immuno Solid-phase Allergen Chip (ISAC), Thermo Fisher Scientific/Phadia AB, Uppsala, Sweden] to standard diagnostic work-up can change the clinicians' views on the diagnosis, management and treatment of patients. There was some indication that the use of ImmunoCAP ISAC testing may be useful to guide decisions on the discontinuation of restrictive diets, the content of allergen-specific immunotherapy (SIT) prescriptions, and whether or not patients should receive SIT. However, none of the studies that we identified reported any information on clinical outcomes subsequent to changes in treatment or management. There was some evidence that ImmunoCAP ISAC may be useful for discriminating allergens that are structurally similar and are recognised by the same IgE antibody (cross-immunoreactive). No data were available for Microtest (Microtest Matrices Ltd, London, UK). Detailed cost analyses suggested that multiplex allergen testing would have to result in a substantial reduction of the proportions of patients receiving single IgE testing and oral food challenge tests in order to be cost-saving in the short term.

CONCLUSIONS

No recommendations for service provision can be made based on the analyses included in this report. It is suggested that a consensus-based protocol for the use of multiplex allergen testing be developed. The clinical effectiveness and cost-effectiveness of the proposed protocol should then be assessed by comparing long-term clinical and quality of life outcomes and resource use in patients managed using the protocol with those managed using a standard diagnostic pathway.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015019739.

FUNDING

This project was a Diagnostic Assessment Report commissioned by the NIHR HTA programme on behalf of the National Institute for Health and Care Excellence.