Are our impressions of allergy test performances correct?

History and Utility of Specific IgE Cutoff Levels: What is the Relevance for Allergy Diagnosis?

Allergy is defined clinically, by symptoms on allergen exposure. A patient is considered sensitized when allergen-specific IgE (sIgE) antibody can be detected in serum or plasma or a skin test result is positive, even if no clinical reaction has been experienced. Sensitization should be regarded as a requisite and risk factor for allergy but is not synonymous with an allergy diagnosis. To provide a correct allergy diagnosis, test results regarding allergen-sIgE must always be considered in view of the patient's case history and clinical observations. Correct assessment of a patient's sensitization to specific allergens relies on the use of accurate and quantitative methods for detection of sIgE antibodies. The evolution of sIgE immunoassays toward higher analytical performance and the use of different cutoff levels in the interpretation of test results sometimes cause confusion. Earlier versions of sIgE assays offered a limit of quantitation of 0.35 kilounits of sIgE per liter (kUA/L), which also became an established cutoff level for a positive test result in the clinical use of the assays. Current sIgE assays are capable of reliably measuring sIgE levels as low as 0.1 kUA/L and can thereby demonstrate sensitization in cases in which previous assays could not. When the outcome of sIgE test results is evaluated, it is critically important to distinguish between the analytical data as such and their clinical interpretation. Even though sIgE may be present in the absence of symptoms of allergy, available information suggests that sIgE concentrations between 0.1 kUA/L and 0.35 kUA/L may be clinically relevant in some individuals, not least among children, although this should be further evaluated for various allergies. Moreover, it is becoming widely adopted that nondichotomous interpretation of sIgE levels may offer a diagnostic benefit compared with using a predefined cutoff level.

House Dust Mite Allergens: New Discoveries and Relevance to the Allergic Patient

PURPOSE OF REVIEW

Recent findings on house dust allergens and their contribution to knowledge that will significantly impact on current and future allergy treatments are appraised.

RECENT FINDINGS

Quantitation of IgE binding to a spectrum of allergen components in several independent studies in varying locations has largely affirmed the main components as the groups 1 and 2 and possibly 23 allergens with mid-tier contributions from the groups 4, 5, 7, and 21. Prevalent binding to Der p 23 has been recapitulated sometimes with low titers. The IgE of non-asthmatic atopic subjects binds at lower titer and to fewer components than that of asthmatics, and their IgG binding relative to IgE is higher especially for children hospitalized for exacerbation. The higher IgG ratios were associated with increased IL-10 a cytokine more readily induced from T cells of allergic subjects. Peptides representing the groups 1 and 2 allergens can be used to stimulate ex vivo T cells showing responses correlating with IgE binding and providing a valuable tool for ascertaining the contribution of IgE and T cells to disease. Also, the induction of Th2 and follicular helper T cells are shown to make different contributions in mice. Cross-reactivity of IgE binding assays with high-titer cross-reactive antibodies induced by scabies is a problem in the many areas of the world where scabies is highly prevalent and endemic and from recent increases in immigration. In the last few years, allergen research has produced results that warrant rapid translation into diagnostic tools and the formulation of allergen components for immunotherapy.

Mold allergy: is it real and what do we do about it?

INTRODUCTION

fungi produce substances that contain pathogen-associated molecular patterns (pamps) and damage-associated molecular patterns (damps) which bind to pattern recognition receptors, stimulating innate immune responses in humans. they also produce allergens that induce production of specific ige. Areas covered: In this review we cover both innate and adaptive immune responses to fungi. Some fungal products can activate both innate and adaptive responses and in doing so, cause an intense and complex health effects. Methods of testing for fungal allergy and evidence for clinical treatment including environmental control are also discussed. In addition, we describe controversial issues including the role of Stachybotrys and mycotoxins in adverse health effects. Expert commentary: Concerns about long-term exposure to fungi have led some patients, attorneys and fungus advocates to promote fears about a condition that has been termed toxic mold syndrome. This syndrome is associated with vague symptoms and is believed to be due to exposure to mycotoxins, though this connection has not been proven. Ultimately, more precise methods are needed to measure both fungal exposure and the resulting health effects. Once that such methods become available, much of the speculation will be replaced by knowledge.

Clinical Evaluation and Management of Patients with Suspected Fungus Sensitivity

Fungus-sensitized patients usually present with symptoms that are similar to symptoms presented by those who are sensitized to other aeroallergens. Therefore, diagnosis and management should follow the same pathways used for patients with allergic conditions in general. The physician should consider that a relationship between fungal exposure and symptoms is not necessarily caused by an IgE-mediated mechanism, even when specific fungal IgE is detected. Until recently, IgE-mediated allergy has been documented only for a limited number of fungi. We propose a series of questions to be used to identify symptoms that occur in situations with high fungal exposure and a limited skin-prick-test panel (Alternaria, Cladosporium, Penicillium, Aspergillus, Candida) that can be amplified only in cases of high suspicion of other fungal exposure (eg, postfloods). We also review in vitro testing for fungi-specific IgE. Treatment includes environmental control, medical management, and, when appropriate, specific immunotherapy. Low-quality evidence exists supporting the use of subcutaneous immunotherapy for Alternaria to treat allergic rhinitis and asthma, and very low quality evidence supports the use of subcutaneous immunotherapy for Cladosporium and sublingual immunotherapy for Alternaria. As is the case for many allergens, evidence for immunotherapy with other fungal extracts is lacking. The so-called toxic mold syndrome is also briefly discussed.

Rationale for specific allergen testing of patients with asthma in the clinical pulmonary office setting

Asthma is a chronic inflammatory disease that affects an estimated 25 million people in the United States. In 70% to 90% of cases, asthma is associated with IgE-mediated mechanisms, which have proved central to allergen-induced inflammation in preclinical and clinical models. The importance of IgE levels in patients with moderate to severe asthma has been confirmed in randomized controlled studies with a targeted IgE blocker. Advances in laboratory methods to detect and quantify allergen-specific IgE antibodies have allowed for a quick-and-easy diagnosis of allergic IgE-mediated sensitivities in the office. Pulmonologists tend to order in vitro tests to measure allergen-specific IgE rather than to perform allergen skin testing, which is seen as the purview of allergists. This article reviews the importance of allergen testing in patients with asthma—whether by skin testing or by in vitro methods—and highlights the advantages, limitations, and interpretation of results derived from each method. Additionally, this article includes suggested documentation and administrative details for physician reporting in the office setting.

Allergy Diagnosis in Children and Adults: Performance of a New Point-of-Care Device, ImmunoCAP Rapid

BACKGROUND

: Allergy is a serious problem affecting approximately 1 of 4 individuals. The symptoms with and without allergy etiology are often difficult to distinguish from each other without using an IgE antibody test. The aim of this study was to investigate the performance of a new point-of-care (POC) test for IgE antibodies to relevant allergens in Europe.

METHODS

: IgE antibodies from children and adults with allergies recruited from allergy clinics in Sweden and Spain were analyzed for 10 allergens, suitable for the age groups, using the new POC test and ImmunoCAP laboratory test. The IgE antibody level best discriminating between positive and negative results (the cutoff point) for the different allergens of the POC test and the efficacy of the POC and the ImmunoCAP laboratory tests for diagnosing allergy compared with that of clinical diagnosis were investigated.

RESULTS

: The estimated cutoffs for the different allergens in the POC test ranged from 0.70 to 2.56 kUA/L. Taking into account all positive allergen results in a given patient, the POC test could identify 95% of the patients with allergies. Seventy-eight percent of the allergen-specific physicians' diagnoses were identified and 97% of the negative ones. Most allergens exhibited good performance, identifying about 80% of clinically relevant cases. However, dog, mugwort, and wall pellitory would benefit from improvement.

CONCLUSIONS

: The POC test will be a valuable adjunct in the identification or exclusion of patients with allergies and their most likely offending allergens, both in specialist and general care settings.

Overview of serological-specific IgE antibody testing in children

Allergic diseases are among the most common chronic conditions in the pediatric population. Allergy diagnostic testing is an important part of the evaluation/management of allergic patients because the history may not be precise enough to identify the specific allergen sensitivity. In addition to providing information about specific sensitivities, allergy diagnostic tests have some predictive value in terms of future risk of developing an allergic condition and the severity/persistence of the allergic disease. The two most commonly used methods of confirming allergen sensitization are skin testing and measurement of serum-specific IgE. Both methods have similar diagnostic value in terms of sensitivity and specificity, with both parameters varying with the clinical scenario and allergen tested. Currently, there are three US Food and Drug Administration-cleared, serum-specific IgE assays used in the United States. The three assays report comparable analytic sensitivity, with the coefficients of variation of the precision, reproducibility, and linearity being less than 15%. However, comparative studies have demonstrated significant inter-assay variability, suggesting that they detect different populations of IgE antibody in human sera or do not measure the same antibodies with the same efficiency. Current specific IgE assays utilize allergen extract reagents. Testing with these reagents may identify sensitivity to clinically irrelevant allergens. This diagnostic limitation has spurred the development of molecular diagnostic tests, also referred to as component-resolved diagnostics, which utilize purified native or recombinant allergens to detect IgE sensitivity to individual allergen molecules. These advancements in serum IgE testing may enhance the precision of allergy diagnostic testing, which may decrease the need for oral food challenges and improve the specificity of allergen immunotherapy.

Diagnostic tools in Rhinology EAACI position paper

This EAACI Task Force document aims at providing the readers with a comprehensive and complete overview of the currently available tools for diagnosis of nasal and sino-nasal disease. We have tried to logically order the different important issues related to history taking, clinical examination and additional investigative tools for evaluation of the severity of sinonasal disease into a consensus document. A panel of European experts in the field of Rhinology has contributed to this consensus document on Diagnostic Tools in Rhinology.

Questionnaire predictors of atopy in a US population sample: findings from the National Health and Nutrition Examination Survey, 2005-2006

Allergic conditions and biochemical measures are both used to characterize atopy. To assess questionnaires' ability to predict biochemical measures of atopy, the authors used data on 5 allergic conditions (allergy, hay fever, eczema, rhinitis, and itchy rash) and serum-specific immunoglobulin E (IgE) levels from the 2005-2006 National Health and Nutrition Examination Survey. Atopy was defined as 1 or more positive specific IgEs (≥0.35 kU/L). Questionnaire responses were assessed for sensitivity, specificity, and positive and negative predictive values for atopy. In this population-based US sample, 44% of participants were specific IgE-positive and 53% reported at least 1 allergic condition. Discordance between atopy and allergic conditions was considerable; 37% of persons with atopy reported no allergic condition, and 48% of persons who reported an allergic condition were not atopic. Thus, no combination of self-reported allergic conditions achieved both high sensitivity and high specificity for IgE. The positive predictive value of reported allergic conditions for atopy ranged from 50% for eczema to 72% for hay fever, while the negative predictive value ranged from 57% for eczema to 65% for any condition. Given the high proportion of asymptomatic participants who were specific IgE-positive and persons who reported allergic conditions but were specific IgE-negative, it is unlikely that questionnaires will ever capture the same participants as those found to be atopic by biochemical measures.

Health-care cost reduction resulting from primary-care allergy testing in children in Italy

Background

Allergy places a considerable cost burden on society. Specific immunoglobulin E (spIgE) testing may improve the management of allergy patients. There is therefore a reason to quantify the economic consequences of the use of spIgE testing in the diagnosis of allergic conditions.

Methods

The expected costs of spIgE testing versus no-testing were calculated using a clinical decision model based on a prospective clinical trial performed in primary care.

Results

The expected costs per patient over 2 years decreased from 802 euros in the "no-test strategy" to 560 euros in the spIgE "test strategy". Cost savings persisted even after assumptions about the prevalence of allergy and the prices of medications were changed. The "test strategy" increased the percentage of patients correctly diagnosed from 54 to 87%.

Conclusions

spIgE testing of children with respiratory and/or skin problems in primary care in Italy reduces overall costs to society. These cost savings mostly result from a reduction in the use of medications, particularly corticosteroids. The study indicates that spIgE testing of all children with respiratory and/or skin symptoms would be a cost-effective strategy.

The role of intradermal skin testing in inhalant allergy

OBJECTIVE

To provide an overview of the role of intradermal skin testing (IDST) in inhalant allergy.

DATA SOURCES

A literature search was conducted in MEDLINE to identify peer-reviewed articles related to IDST using the following keywords: skin testing, intradermal, intracutaneous, aeroallergen, and inhalant allergen. In addition, references cited within these articles were also reviewed.

STUDY SELECTION

Articles were selected based on their relevance to the topic.

RESULTS

The use of IDST for inhalant allergy varies widely among allergists. When performed, it is necessary to use a 100- to 1,000-fold dilution from the stock allergen extract. IDST is used routinely in the standardization of extracts in the United States. With a negative skin prick test result, a positive IDST result has low agreement with in vitro and challenge results and generally adds little to the diagnostic evaluation. In contrast, a negative IDST result generally has a high negative predictive value. Only a few inhalant allergens have been evaluated with challenge models for IDST. A summary of the data is also presented in tabular form.

CONCLUSIONS

Most of the literature suggests that with a negative skin prick test result, a positive IDST result adds little to the diagnostic evaluation of inhalant allergy. However, additional studies are necessary using challenge models for less potent and nonstandardized inhalant allergens (molds, trees, dog, weeds).

Diagnostic tests for human allergic disease

BACKGROUND

The diagnosis of human allergic disease begins with a thorough clinical history and physical examination. Once a temporal relationship has been identified between a patient's history of allergic symptoms and a defined allergen exposure, confirmatory analyses for IgE antibody involving skin or blood testing are performed to verify sensitization. Debate continues over the relative diagnostic utility of the in vivo and in vitro measures of IgE antibody.

OBJECTIVE

This overview examines the strengths and limitations of primary diagnostic confirmatory methods for in vivo detection (skin test, provocation test) and in vitro quantification of IgE antibody.

METHODS

A literature review was performed to examine diagnostic performance characteristics and variables that influence the accuracy of IgE antibody assays.

DISCUSSION

The clinical history and both in vivo and in vitro measures of IgE antibody are subject to variability and potential patient, clinician and technician-related bias. As such, in the absence of an absolute clinical history-based gold standard for defining the presence of allergic disease, the relative diagnostic performance (sensitivity, specificity) of in vivo versus in vitro assays of IgE antibody cannot be effectively determined. The review examines which allergic disease states and allergen specificities allow both groups of IgE antibody assays to produce comparable qualitative data for assessing the state of allergic sensitization. Skin testing has experienced few recent technological innovations, whereas an explosion has occurred in the improved performance (analytical sensitivity and specificity) of in vitro assays and enhanced quality of reagents for IgE antibody quantification. This review discusses the impact of point of care-testing assays, microarrays, the use of native and recombinant allergen molecules, automation, and disease prediction algorithms and the 2008 Clinical and Laboratory Standards Institute Guideline on IgE antibody methods, on the diagnosis of human allergic disease.

Testing for allergic disease: parameters considered and test value

BACKGROUND

Test results for allergic disease are especially valuable to allergists and family physicians for clinical evaluation, decisions to treat, and to determine needs for referral.

METHODS

This study used a repeated measures design (conjoint analysis) to examine trade offs among clinical parameters that influence the decision of family physicians to use specific IgE blood testing as a diagnostic aid for patients suspected of having allergic rhinitis. Data were extracted from a random sample of 50 family physicians in the Southeastern United States. Physicians evaluated 11 patient profiles containing four clinical parameters: symptom severity (low, medium, high), symptom length (5, 10, 20 years), family history (both parents, mother, neither), and medication use (prescribed antihistamines, nasal spray, over-the-counter medications). Decision to recommend specific IgE testing was elicited as a "yes" or "no" response. Perceived value of specific IgE blood testing was evaluated according to usefulness as a diagnostic tool compared to skin testing, and not testing.

RESULTS

The highest odds ratios (OR) associated with decisions to test for allergic rhinitis were obtained for symptom severity (OR, 12.11; 95%CI, 7.1-20.7) and length of symptoms (OR, 1.46; 95%CI, 0.96-2.2) with family history having significant influence in the decision. A moderately positive association between testing issues and testing value was revealed (beta = 0.624, t = 5.296, p < or = 0.001) with 39% of the variance explained by the regression model.

CONCLUSION

The most important parameters considered when testing for allergic rhinitis relate to symptom severity, length of symptoms, and family history. Family physicians recognize that specific IgE blood testing is valuable to their practice.

Maternal positive skin prick test results and asthma prediction after early childhood wheezing

BACKGROUND

Previous studies have used parental history of asthma or allergy but not positive skin prick test results to predict the evolution of asthma in wheezing infants.

OBJECTIVE

To determine whether positive parental skin prick test results serve as a predictive factor for the subsequent development of asthma in a child with a history of wheezing before the age of 3 years.

METHODS

In a retrospective cohort study we investigated 91 individuals from 71 families. Enrollment criteria were age 6 to 40 years, history of wheezing before the age of 3 years, and no chronic lung disease other than asthma. Each participant was asked about current asthma-related symptoms, underwent pulmonary function testing, and underwent skin prick testing. Participants' parents underwent skin prick testing and measurement of total serum IgE levels.

RESULTS

Asthma was diagnosed in 56 participants (61%). Although maternal positive skin prick test results conferred a 3.4-fold risk of asthma (P = .02), neither the mother's nor the father's self-reported allergy or asthma was predictive of later development of asthma.

CONCLUSION

The presence of parental, and especially maternal, positive skin prick test results is a significant predictive factor for the subsequent development of asthma in early childhood wheezing.

Accuracy of IgE antibody laboratory results

BACKGROUND

Studies have demonstrated that the magnitude of sensitization as evidenced by specific IgE (sIgE) levels provides significant information as to whether a sensitized individual is likely to be truly reactive. However, it is not clear that quantitative sIgE results provided by different laboratories using different technologies are comparable.

OBJECTIVE

To investigate whether similar results were obtained from Clinical Laboratory Improvement Act-certified laboratories that used 3 common systems for sIgE antibody determination with serum samples and mouse-human IgE chimeric antibodies with known specificity and quantity.

METHODS

Sixty samples for peanut and 20 for soy were submitted for sIgE determination on 3 different systems: ImmunoCAP, Immulite, and Turbo radioallergosorbent test (RAST). Mouse-human chimeric IgE antibodies specific for the major birch allergen Bet v 1 and for the dust mite allergen Der p 2 were also included.

RESULTS

A qualitative evaluation using a cutoff of 0.35 kUA/L showed some differences in the ability to detect sIgE sensitization, with the Turbo RAST being most variable. However, considerable differences were found with quantitative evaluation, with Immulite overestimating and Turbo RAST underestimating sIgE compared with ImmunoCAP. Similar discrepancies were seen with the mouse-human chimeric IgE antibody samples.

CONCLUSION

These findings have potentially serious clinical implications, since each of these systems is widely used. It is therefore important that all laboratories clarify which system they are using. Just because 2 systems present their results in the same units does not mean that the results are necessarily correct or interchangeable.

Evidence-based allergy diagnostic tests

Effective management of allergic diseases relies on the ability to make an accurate diagnosis. Although clinicians rely on experience obtained over many years of practice, such experience is anecdotal and unique to the individual using it. The result is a tendency for patients with similar clinical presentations to receive different diagnoses and treatment, depending on which provider they happened to see. The probability that a patient has a particular diagnosis can be determined using a combination of diagnostic tests. To make the best use of tests, it is important to understand their performance characteristics in terms of reproducibility and likelihood ratios. A test that is reproducible but that does not predict the presence of a disease is not helpful, nor is an accurate test that is not reproducible. To improve the reproducibility of diagnostic tests, it is important that proficiency testing be instituted for both skin and in vitro tests so that the coefficient of variance can be determined. This has already been done for the latter and needs to be done for skin tests as well. With use of a combination of history and appropriate diagnostic tests, the probability that a particular diagnosis is present can be increased or decreased sufficiently either to confirm it or to rule it out. As proficiency testing of allergy tests becomes more common and the use of tests becomes more consistent, we believe that patients with allergic diseases will benefit.

ImmunoCAP Phadiatop Infant--a new blood test for detecting IgE sensitisation in children at 2 years of age

BACKGROUND

Correct diagnosis of immunoglobulin E (IgE)-mediated disease is the prerequisite for secondary allergy prevention during early childhood.

OBJECTIVE

To evaluate the diagnostic efficacy of a new blood test, Phadiatop Infant, in detecting IgE sensitisation to food and inhalant allergens among children at 2 years of age.

METHODS

Children (n = 239) were followed prospectively from birth to 2 years of age for the presence of IgE sensitisation and the development of atopic manifestations. Immunoglobulin E sensitisation was evaluated by skin prick test (SPT) and analysis of allergen-specific IgE antibodies in plasma to food and inhalant allergens. The children were classified into three groups: IgE-sensitised, non-IgE sensitised and inconclusive, depending on SPT and allergen-specific IgE results.

RESULTS

Twenty-six (11%) of the children were classified as IgE-sensitised, 182 (76%) as non-IgE sensitised and 31 (13%) as inconclusive. Phadiatop Infant was positive in 50 (21%) of the children. Ten children (4%) with identified IgE antibodies against the selected food and inhalant allergens showed negative Phadiatop Infant. Three children showed positive Phadiatop Infant but were negative in the other tests performed. These results correspond to positive and negative predictive values for Phadiatop Infant of 89 and 99%, respectively. Children with clinical symptoms of atopic diseases had significantly increased levels for Phadiatop Infant (P < 0.01).

CONCLUSION

Phadiatop Infant appears to be a reliable alternative to SPT and the measurement of allergen-specific IgE antibodies in plasma for detecting clinically important IgE sensitisation among children at 2 years of age.

High prevalence of IgE antibodies among blood donors in Sweden and Norway

BACKGROUND

Reactions after a blood transfusion could be allergic because of passive transfer of immunoglobulin E (IgE) antibodies from allergic donors.

AIMS OF THE STUDY

To compare spectrum and prevalence of IgE antibodies in blood donors from Sweden and Norway.

METHODS

Using the ImmunoCAP method, serum samples from 1002 blood donors from Sweden and 500 from Norway were analysed for IgE antibodies to common inhalant and food allergens and allergens common in a hospital environment, such as penicilloyl G and latex.

RESULTS

As many as 23.6-27.3% of the donors had IgE antibodies to at least one of the 14 allergens tested. Of these 6.8-16.7% had extremely high concentrations, i.e. >35 kU(A)/l corresponding to 100 times the cut-off for a positive allergy test. Most donors were sensitized to pollens, dander and mite but several had very high levels of IgE antibodies to penicilloyl G, latex and peanut. The pattern of sensitizing allergens differed between Sweden and Norway.

CONCLUSIONS

High serum levels of IgE antibodies to various allergens are common among blood donors and the degree of sensitization and spectrum of involved allergen varies between geographical regions. Present routines to identify IgE sensitized, potential risk, donors are not satisfactory; the sensitivity of selection procedures is about 25%.

Influence of patient care provider on patient health outcomes in allergic rhinitis

BACKGROUND

Diagnosing and managing the symptoms of allergic rhinitis are largely the responsibility of family physicians and allergists, but some patients choose self-management. However, few data are available to determine how the choice of care relates to measures of patient outcomes, such as the ability to perform activities, quality of life, and productivity.

OBJECTIVE

To examine and compare patients' ability to perform activities, quality of life, productivity, and symptoms according to care provider: family physician, allergist, or self-management.

METHODS

A questionnaire was developed and mailed to 2,065 patients enrolled in a 500,000-member managed care organization. Patients were identified by diagnostic codes for allergic rhinitis as determined from a retrospective examination of medical and prescription claims records between January 1, 2000, and December 31, 2000.

RESULTS

Chi-squared Tests revealed statistically significant differences for symptoms, family history, testing, immunotherapy, and test value among patient care providers. Multivariate analysis of variance revealed statistically significant differences for activities, symptoms, and quality of life among patient care providers. Findings support the use of diagnostic testing to improve patient outcomes. Symptoms were statistically significantly associated with measures of productivity.

CONCLUSIONS

Patient outcomes vary with respect to patient care group. It is imperative that patients suspected of having allergic rhinitis undergo appropriate evaluation and testing. Outcomes can be optimized if allergists and family physicians have access to appropriate diagnostic tools, such as skin testing and serologic tests for specific IgE antibodies.

Evidence-based strategies for treatment of allergic rhinitis

In this review, an evidence-based medicine approach to diagnosis and treatment for allergic rhinitis is reviewed. We performed a search of the medical literature for randomized, placebo-controlled trials of nonsedating antihistamines, intranasal corticosteroids, montelukast, azelastine, allergen immunotherapy, and anti-IgE. The mean numbers needed to treat were: nonsedating antihistamines--15.2; nasal corticosteroids--4.4; montelukast--14.3; azelastine--5.0; allergen immunotherapy--4.6; and anti-IgE--12.4. Treatment thresholds for use were: antihistamines--23%; nasal corticosteroids--8%; azelastine--16%; montelukast--8%; anti-IgE--50%; and immunotherapy--25%. When used appropriately, this information could become very useful for clinicians, particularly if cost, convenience, and other indirect factors can be included.

Diet and the development of atopic disease

PURPOSE OF REVIEW

The present review addresses the current literature regarding the impact of diet and the development of atopic disease. A search of the literature was carried out covering the following topics: diet and nutrition combined with immediate hypersensitivity, atopy, atopic disease, atopic dermatitis, and food allergy.

RECENT FINDINGS

The search results identified a significant contribution in the form of reviews considering this important topic, which ultimately led to the author's recommendation of these reviews to impress upon readers the impact of the atopy triad: atopic dermatitis to allergic rhinitis and asthma.

SUMMARY

A great deal of information exists in the pathomechanisms of atopic disease that will affect the classification of allergic and non-allergic atopic diseases. Increasing data on the genetic, humoral and cellular forms associated with these diseases will provide more clear-cut diagnostic criteria, treatment regimens and a more strict definition of the disease variants.

ImmunoCAP Specific IgE test: an objective tool for research and routine allergy diagnosis

Immunoglobulin (Ig) E-mediated allergic diseases are increasing rapidly, affecting the quality of life of millions of people and causing enormous costs for society. Accurately identifying the sensitizing allergen and its sources is one of the cornerstones in the clinical management of allergic patients. The original ImmunoCAP Specific IgE test (Pharmacia Diagnostics) is the only test for IgE antibodies sufficiently documented and recommended in research for advanced diagnosis and risk assessment. It is a reliable diagnostic tool and particularly useful in primary care where the use of in vivo tests cannot be recommended if the personnel have insufficient opportunities to get the appropriate experience.

In vitro assays for the diagnosis of IgE-mediated disorders

Advances in technology have provided new laboratory tools for the quantitation of allergen-specific IgE antibodies in serum and on the surface of basophils. This review examines the evolution from qualitative IgE antibody assays of the late 1960s to the present-day, third-generation, automated and quantitative allergen-specific IgE assays. The latest technology trend is toward microarrays in which crude or purified native and recombinant allergens can be spotted in microdot arrays on silica chips to permit extensive panels of specific IgE measurements to be performed with small quantities of serum. Although these technologies hold promise, their diagnostic performance requires further assessment once their technical details have been optimized. Potential abuses of this newer IgE antibody technology include the use of allergosorbent specificities (eg, especially food and drugs) that lack validation, application of IgE antibody measurements in the diagnosis of non-IgE-dependent disorders (eg, aspirin sensitivity), and modification of IgE antibody assays to measure food-specific IgG antibody for which there is no clinical indication. Basophil mediator release assays have evolved to include flow cytometric methods that can quantitatively detect the presence of cell surface-bound allergen-specific IgE antibodies. Assays for histamine and leukotriene C 4 released after in vitro basophil activation are now more accurate and standardized. Current analytic methods for IgE antibodies provide more quantitative and reproducible measurements of IgE than ever before, although still with less sensitivity that traditional skin testing. The current challenge is to translate the quantitative IgE antibody results into a more accurate diagnosis of allergic disease.

Usefulness of specific IgE antibody tests: a progress report

LEARNING OBJECTIVES

To enable the readers to recognize some of the history, problems, progress, interpretation, and present status of assays for specific IgE (s-IgE) antibodies.

DATA SOURCES

Peer-reviewed literature in the field.

STUDY SELECTION

Key articles were selected by the author.

RESULTS

Clinical and analytical studies have differed widely in their conclusions as to the performance of tests for s-IgE. Study conclusions depend on the testing method used, the allergen(s) studied, patient selection, and, most importantly, the standards used for comparison. Today, only a handful of the once commercially developed assays still exist, and some of these still do not compare well to an analytical ideal standard. However, with the extent of regulation and economic pressures, most of the surviving s-IgE tests are considerably improved over what had existed before them.

CONCLUSIONS

Allergic diseases with multiple symptom patterns seem to be increasing in modern societies. Objective methods are needed to differentiate allergic origins from other mechanisms that cause similar symptoms. Accurate, quantitative, and objective methods for s-IgE measurement are now available and can be used effectively in clarifying allergic diagnoses when interpreted in conjunction with the clinical history.