Ordering 101: Frequently asked questions about allergy diagnostics

As a primary care provider, you see it all. You are everyone’s first stop when something doesn’t feel right or a nagging issue just won’t go away. This means you’re also the first stop for your patients who may have allergies but aren’t sure which ones — or if their symptoms are even an allergy at all. In fact, nearly 80% of patients with allergy-like symptoms are treated in primary care settings.¹

But ordering a blood test to aid in allergy diagnosis isn’t always straightforward. There are numerous tests across food and respiratory allergies. There is skin prick testing vs. blood testing to help diagnose allergic diseases. There is testing with whole allergens vs. allergen components. There are laboratory test codes that can change. And then there are potential billing issues with insurance if an incorrect billing code is used.

The good news is that there are solutions and resources to address these challenges. Ruling allergies in or out is a vital component of primary care because allergies can overlap with conditions like asthma or rhinitis.² If a patient is experiencing symptoms from an allergic sensitization, getting to the root cause is crucial for their symptom management and overall well-being. 

Thermo Fisher Scientific is always working to improve diagnostic testing and gets plenty of questions about ordering specific IgE blood tests and interpreting results. About a quarter (26%) of primary care providers say they’re confident in doing so, which means that three-quarters have questions.³ That's why we’ve answered these frequently asked questions about ordering. Take a look at some of the most common questions (and answers) so you can more easily provide insights and guidance to your patients.

Why should I order specific IgE blood tests for allergies?

Because they’re more thorough.⁴ Specific IgE blood tests have been found to increase accuracy in allergy diagnosis, particularly in terms of identifying genuine allergies or cross-reactivity.⁴ They can also help stratify patient risk levels for systemic versus local reactions.⁴ They assist in providing guidance for understanding allergic reactions, avoiding allergic triggers, and can improve symptom management for patients. Specific IgE tests can provide a level of granularity that, for example, clinicians can help identify if a patient can tolerate baked milk or baked egg but will experience a reaction to fresh or lightly cooked forms of these food allergens.⁵

Which test(s) should I choose?

Getting a thorough patient history and a list of symptoms is key in taking the next step and ordering a test. For example, if a history and symptoms indicate a potential respiratory allergy, you can order a respiratory profile that will include indoor and outdoor allergens. A "profile" means a specific selection of allergens that will be tested. A typical respiratory profile will include outdoor allergens that are specific to that region, as well as indoor allergens like pets and dust mites.

If a history and symptoms indicate a potential food allergy, you can order a test to measure the sensitization to the specific foods suspected. When specific foods aren't identified from history, it's important to test only for the most common food allergen types. Large, indiscriminate profiles that include many unnecessary food allergens are never appropriate.⁶

The other important selection is to choose a profile with allergen component reflex in the name (if available). Allergen component reflex tests provide more detailed information than whole allergen tests alone. If a whole allergen comes back positive, the components of that allergen are automatically tested to get a more granular picture of the patient’s sensitization. This means:

• No repeat blood draws.
• No additional billing or claims to submit to insurance.
• Better identification of triggers (raw foods versus cooked, male or female dogs, etc.)⁴

How do I find the right laboratory test code?

You can find the appropriate allergen profiles and their corresponding test codes by using the Lab Ordering Guide. This resource identifies profiles based on your location. If you search for a respiratory profile, the search results will be relevant to your geographic region or area. If you suspect a food allergy and search for a food profile, results will include profiles that include the nine major food allergens. 

The Lab Ordering Guide also ensures that you can work with labs that you’re familiar with since you can choose from the most relevant codes in your area. And, you can copy codes directly from the guide to simplify the ordering process.

I ordered a test with a lab code I’ve used before, but it was invalid. Why do these codes change? 

As new research is shared about sensitization patterns, assays are updated accordingly. It’s important to continually evaluate trends and changes in allergy and immunology diagnosis and treatment so that the most updated, comprehensive tests can be provided. 

The result is that occasionally laboratory test codes will change when assays change. Our Lab Ordering Guide is therefore your most up-to-date resource for accurate codes relevant to your region and available at your local labs.

What about coverage and reimbursement?

It's critical to remember that specific IgE diagnostic tests are an aid in the diagnosis of suspected allergic disorders and not screening tools. In patients presenting with allergy-like symptoms, a specific IgE blood test may be appropriate, and the correct diagnostic code should be selected to avoid potential coverage and reimbursement issues. See these common, potentially relevant ICD-10 diagnosis codes for details.

Testing should be based upon symptoms. It is typically not appropriate to test for sensitization to food allergens if a patient is presenting with respiratory allergy-like symptoms. Repeated tests in a short timeframe are also less likely to be reimbursed. With a few best practices, you can be more confident about reimbursement:

• Use diagnostic codes.
• Order the appropriate profile based on symptoms.
• Test only as often as necessary.
• Choose component reflex profiles to avoid running multiple tests.

How do I interpret the test results?

Primary care providers are constantly seeing all sorts of symptoms and conditions –that includes potential allergy symptoms. To help you analyze the test results and provide guidance to your patients, we have interpretation guides ranging from respiratory and food allergen components to stinging insects. 

These guides, along with patient history and exam information, can assist healthcare providers in developing patient care strategies. For example, if a patient is sensitized to multiple allergens with cross-reactivity, you’ll be better equipped to help them avoid triggers or prescribe the most appropriate medication.² These test results can also help you determine if referrals to specialists are necessary.²

Get more support to help your patients with suspected allergies

Test ordering and interpretation can seem daunting, but we’re here to help. Check out some of these additional resources that can aid in helping your patients with suspected allergies.