Understanding Allergies from Bedside to Blood Test

Clinical services have historically embraced nurse practitioners (NPs) to deliver allergy care, including diagnosing allergy and interpreting blood test results. NPs play a vital role in diagnosing and managing allergies in patients with asthma. Among 7.7% of Americans with asthma, about two-thirds have a clinical allergy.^1,2

Most patients with asthma are managed by primary care clinicians, with only 22% regularly treated by a specialist.³ According to the Centers for Disease Control and Prevention (CDC), about 40% of primary care visits are for chronic conditions.⁴ With clinician shortages and longer wait times for both primary care providers and allergists, specific IgE (sIgE) blood testing offers a cost-effective, efficient option for care teams, including NPs, to get to the root causes of their patients’ symptoms. Blood tests can help improve allergy and asthma management, reduce the risk for related complications, save clinicians’ time by preventing unscheduled appointments, and improve patient safety and outcomes in the long term.

Why allergy histories matter in clinical care

There are a few important factors to keep in mind when establishing a patient’s history during a primary care visit. It can be easy for patients to confuse allergies, sensitivities, and side effects, which can lead to inaccurate chart notes.

Symptom records could be documented without clarification. For example, an adult patient may reference a reaction they once had as a child but their records may not state the age they had the reaction. Incomplete or inaccurate patient histories can create long-term chart errors and undermine clinical decision-making.

This is why capturing a patient’s clinical history is the most important step of the diagnostic process. A thorough patient history should assess symptoms consistent with IgE-mediated allergy. These reactions, typically occurring within minutes to a few hours after allergen exposure, can affect the skin, gastrointestinal tract, cardiovascular system, and/or respiratory tract. An exception is certain delayed responses, such as those seen in alpha-gal syndrome, a mammalian meat allergy.

Clinicians should document when symptoms occur, their frequency, potential triggers, the location of where they occurred (i.e. work or home), and eating habits to help identify possible food and environmental allergens. Reactions should also be consistently reproducible under similar conditions to support an accurate diagnosis.

Allergy testing in practice

Many patients never receive confirmatory testing of their allergies, with most allergy histories relying on self-reported data. Up to 35% of people self-diagnose food allergy or intolerance to foods and self-manage the condition, rather than seek a clinical diagnosis.⁵ Individuals who self-diagnose may adopt restrictive diets that can cause avoidable nutritional gaps, spending money on ineffective supplements, or taking antihistamines unnecessarily, all while the root cause of their symptoms remains unaddressed.

Moreover, researchers have long known that the frequency of children with allergies who also have asthma can be as high as 90%.² Recent research has shown that about 75% of adults aged 20 to 40 years with asthma, and 65% of those with asthma aged ≥ 55 years have ≥ 1 allergic trigger.² For allergy patients who are wheezing or coughing, care teams can help them devise a treatment plan to manage both their respiratory allergies and asthma.

In vitro blood tests, including ImmunoCAP™specific IgE methods, are essential for identifying patients’ allergic triggers.⁶ These tests, comparable to skin prick testing, measures the amount of specific IgE antibodies that develop as an immune response to allergens and are easily accessible to both specialty and primary care clinicians. This specific IgE testing is commonly offered for common indoor allergens alongside region-specific respiratory allergens (i.e. local grass, tree, and weed pollen) to to help determine the environmental factors that affect patients living in their geographical area.

Serological testing for specific IgE is convenient for patients and only requires a relatively small amount of sera to assess a comprehensive profile of suspected allergens. This test can also help determine if a patient is atopic, meaning that they have a genetic predisposition to develop allergic conditions like asthma, allergic rhinitis, and atopic dermatitis.⁷ Unlike skin prick testing, there is no need for patients to stop any medications before testing. The availability of these clinical laboratory profiles across national and regional locations makes allergy testing an affordable tool that NPs can integrate into their routine asthma and allergy management.

The role of patient education in allergy management

Identifying allergic triggers through specific IgE testing enables the development of customized treatment plans that combine exposure reduction strategies with appropriate medications. NPs play a critical role by helping to provide tailored education on how to avoid food and environmental allergen exposure and to wok along alongside the patient’s broader care team to empower them to understand and manage their symptoms. Educating the patient can help reduce anxiety, improve medication adherence, and create safer home and school environments, leading to improved long-term health outcomes.

References

1. ACAAI. Facts and Stats - 8.3% of Americans Have Asthma. ACAAI Patient. Published 2023. https://acaai.org/asthma/asthma-101/facts-stats/

2. .What does asthma have to do with your allergies? Probably a lot. ACAAI Public Website. Published July 14, 2023. https://acaai.org/resource/what-does-asthma-have-to-do-with-your-allergies-probably-a-lot/

3. Stepanović A, Kopač P, Rotar Pavlič D. Family Physicians’ Awareness of the Burden of Oral Corticosteroids in Asthma Patients. Acta Medica Academica. Published online August 1, 2024. doi:https://doi.org/10.5644/ama2006-124.446

4. Ashman J, Santo L, Okeyode T. Characteristics of Office-based Physician Visits by Age, 2019. National Health Statistics Reports Number. 2023;184(184). https://www.cdc.gov/nchs/data/nhsr/nhsr184.pdf

5. Knibb R. Why Do People Misdiagnose Themselves with Food Hypersensitivity? An Exploration of the Role of Biopsychosocial Factors. https://www.emjreviews.com/wp-content/uploads/2019/03/Why-Do-People-Misdiagnose-Themselves-with....pdf

6. ImmunoCAP^TM Allergy Testing Solutions ImmunoCAP^TM Allergy Testing Solutions. Thermo Fisher Scientific. Published 2017. https://www.thermofisher.com/phadia/us/en/our-solutions/immunocap-allergy-solutions.html

7. Atopy: Disease, Causes, Triggers, Conditions & Treatment. Cleveland Clinic. Published October 3, 2024. https://my.clevelandclinic.org/health/diseases/atopy