A new survey has shown there are large variations in the use and interpretation of a new type of allergy test (component testing) by doctors in the UK and Europe. As a result of these findings, a new quality assurance scheme is being launched to ensure proper quality assessment and education about the performance and use of the tests. The paper was published in Clinical & Experimental Immunology.
Rates of allergy are on the rise and it is estimated that approximately one in three people have an allergy of some type. Tests for individual allergies in the past have had drawbacks including lower reliability levels and difficulty in distinguishing between true and false positive tests. Recent improvements in molecular techniques have allowed us to develop more precise diagnostic procedures that can pinpoint the exact proteins within a substance that cause the allergic reaction. This type of test is called allergen component testing and is rapidly being brought into clinical practice across the UK and Europe. It has the advantage over a traditional skin prick challenge for allergy in that it is more accurate (leading to fewer false positive results - where the skin prick challenge shows positive to a certain food, but the person does not experience an allergic reaction when they actually eat that food); reduces the need for further testing (particularly important with food challenges, which could lead to severe allergic reaction), may avoid speculative dietary exclusions and assists in identifying patients suitable for further treatments, such as specific immunotherapy. However, allergen component testing is a new technology and it's important that both clinicians and laboratory personnel are properly trained in its use and interpretation. Because allergy expertise is rare and tests can be difficult to interpret, many centres will screen test requests to ensure they get the most appropriate tests, or will only offer them to expert users or when accompanied by enough information to interpret the results effectively (often via an allergy questionnaire).
UK NEQAS (the provider of external quality assessment of diagnostic tests for the NHS) carried out a survey of UK and European laboratories offering allergy testing to assess service provision of these new allergen component tests, to see how frequently they were being used, by whom and in what circumstances.
They found that there was a large variation in usage, both within and between the UK and Europe, with a lack of standardised approach across and within clinical services. Allergen component testing was offered by 78% of responding centres (24% UK centres, 58% non-UK EU centres, and 18% centres elsewhere). Only just over half of laboratories (55%) reported screening allergy requests on receipt for appropriateness, but most (95%) did not require a completed allergy questionnaire to be submitted (which would ensure sufficient information is available to allow appropriate testing and useful interpretation). This was despite the laboratories reporting that they felt knowledge of allergen component testing was sub-optimal in both primary and secondary care providers.
Although allergen component testing offers great potential to patients in terms of personalising their allergy diagnosis and treatment, it is vital that these tests are performed well and interpreted correctly, and this needs to be independently assessed by external quality assessment providers. As a result of the demonstration of need, UK NEQAS has now introduced a new pilot quality assessment scheme for labs to work towards ensuring a standardised approach to performing these tests and will incorporate educational cases into its web based interpretive External Quality Assessment scheme. Additionally, they recommend that clinicians involved in commissioning and interpreting these tests should receive adequate training, along with increased awareness of national guidelines reacting to allergen component testing.
Dr William Egner, Director of UK NEQAS Immunology, Immunochemistry and Allergy and study author, said:
"These new types of personalised allergy tests are rapidly becoming more widely available in the UK and Europe. These tests are good for patients as they allow more accurate diagnosis and treatment of allergies. However, for patient safety, it's very important that these allergy tests are administered and interpreted in a standardised way to ensure that the test is done properly and that the results are similar, no matter where and when the test is performed.
"From the findings of this survey, UK NEQAS has introduced a new pilot quality assurance scheme to monitor use of these tests across the UK and Europe and make sure that patients can have confidence in their test results. Additionally, our study showed the need for agreed guidance and education to inform best practice and to standardise care given by healthcare professionals from all fields, including GPs, hospital consultants and laboratory staff."
Article: UK NEQAS survey of allergen component testing across the United Kingdom and other European countries, Saleem, R, Keymer, C, Patel, D, Egner, W & Rowbottom, AW., Clinical & Experimental Immunology, doi:10.1111/cei.12950, published online 19 April 2017.