Latest Review Date: October 2024

Category: Laboratory

POLICY:

Antigen Leukocyte Antibody Test is considered investigational for all indications.

DESCRIPTION OF PROCEDURE OR SERVICE:

The Antigen Leukocyte Antibody Test (ALCAT) is intended to diagnose intolerance to foods and other environmental agents. It is a blood test that assesses the response of leukocytes and platelets to a panel of foods and/or other environmental agents by measuring the change in size and number of cells following exposure to a specific agent.

Intolerance of Environmental Agents or Food

Environmental illness refers to a physiologic reaction that is triggered by an exogenous agent, which can be ingested, inhaled, or absorbed through direct contact with skin. The physiologic reaction can be an immunologic response or a nonimmunologic response. An adverse physiologic reaction to exogenous antigens has been proposed to play a causative role in a wide variety of illnesses, including allergies, gastrointestinal tract disorders such as irritable bowel syndrome, eczema, chronic fatigue, and migraine headache.

Food allergy is the most well-defined type of environmental illness and is estimated to affect 8% of children. In most cases, true food allergy is characterized by a classic immunologic response (i.e., an immunoglobulin E-mediated reaction in response to a specific protein allergen). Reactions can range from mild symptoms to life-threatening anaphylaxis. Current guidelines for the diagnosis and management of food allergies have been developed by the National Institute of Allergy and Infectious Disease.

Food intolerance is a broader term that overlaps with food allergy but is less well-defined. Food intolerance refers to physiologic reactions that are triggered by a particular food but which are not immune-mediated. It is hypothesized that physiologic reactions to food may manifest as a range of nonspecific symptoms, such as gastrointestinal complaints, headache, fatigue, and musculoskeletal complaints and that these symptoms may become chronic with repeated exposure. An example of food intolerance, distinguished from a true food allergy, is lactose intolerance, in which dairy products incite a nonimmunologic reaction that can lead to a constellation of gastrointestinal symptoms.

Treatment of environmental illness primarily involves avoidance of the inciting agent. Acute allergic reactions are treated in the same way as other types of allergies, with antihistamines, steroids, and supportive measures. In cases of a severe allergy where an agent cannot be definitively avoided, patients can carry and self-administer auto-injectable epinephrine when needed. Prophylactic antihistamines can also be used to prevent or lessen reactions. Allergy immunotherapy may be appropriate for selected allergens.

For patients with food intolerance that is not allergy based, identification of the inciting agent(s) can be difficult because the symptoms are chronic. Use of an elimination diet is considered the best way to identify intolerant agents. In an elimination diet, one specific food or food group is eliminated from the diet for a specified period, and symptoms are observed. Following the elimination period, a re-challenge can be performed to ascertain whether symptoms return. Elimination diets often need to be done sequentially with a large number of items, so the process can be lengthy and cumbersome.

Antigen Leukocyte Antibody Test

The Antigen Leukocyte Antibody Test (ALCAT) test is intended to identify foods and other environmental agents for which an individual may be intolerant. It is not intended to diagnose food allergies. The test is based on the theory that a substantial increase in leukocyte size and number is characteristic of an intolerant response. Identifying the specific inciting agent facilitates avoidance of that agent, which may lead to a reduction in symptoms. In this regard, ALCAT testing has been used as a tool for developing an elimination diet that targets the most likely offending agents.

The test is performed by taking a sample of blood, which is first treated to remove the red blood cells and then tested to determine the baseline number and size of leukocytes and platelets. Measurement of size and count of cells is performed by the Coulter technique, which is a standard technique in clinical hematology. Next, a small quantity of blood is incubated with multiple agents. Following exposures, change in the number and size of cells is determined for each exposure. A 10% increase in the size of leukocytes is considered characteristic of a response to an intolerant agent.

The ALCAT website (Cell Sciences Systems) lists 11 separate panels consisting of various combinations of foods, herbs, food additives/coloring, and environmental chemicals. The total number of agents tested in these panels ranges from 81 to 370.

KEY POINTS:

The most recent literature review was performed through August 16, 2024.

Summary of Evidence

For individuals who have a suspected intolerance of environmental agents or food who receive the Antigen Leukocyte Antibody Test (ALCAT), the evidence includes a randomized controlled trial and case series. Relevant outcomes are morbid events and medication use. There is a lack of published research on the diagnostic accuracy of ALCAT; therefore, it is not possible to determine the sensitivity, specificity, and/or predictive value of the test compared with alternatives. A few low-quality studies have reported improvements in outcomes following the use of ALCAT, but it is not possible to determine whether these changes occurred as a result of the test itself, bias, variation in the natural history of the condition, and/or the placebo effect. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Practice Guidelines and Position Statements

National Institute of Allergy and Infectious Disease

In 2010, the National Institute of Allergy and Infectious Disease published guidelines on the diagnosis and management of food allergy. These guidelines defined and distinguished food intolerance from food allergy but did not provide recommendations.

U.S. Preventive Services Task Force Recommendations

Not applicable.

KEY WORDS:

Antigen leukocyte cellular antibody test, ALCAT, Life Eating and Performance (LEAP), Mediator Release Testing (MRT), IgE concentration food allergy testing, IgG Food and Environmental testing, Enzyme-Linked, Immunosorbent Assay, environmental illness, food intolerance, food allergy

APPROVED BY GOVERNING BODIES:

Clinical laboratories may develop and validate tests in-house and market them as a laboratory service; laboratory-developed tests must meet the general regulatory standards of the Clinical Laboratory Improvement Amendments. The ALCAT is available under the auspices of the Clinical Laboratory Improvement Amendments. Laboratories that offer laboratory-developed tests must be licensed by the Clinical Laboratory Improvement Amendments for high-complexity testing. To date, the U.S. Food and Drug Administration has chosen not to require any regulatory review of this test.

BENEFIT APPLICATION:

Coverage is subject to member’s specific benefits. Group-specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply.

FEP contracts: Special benefit consideration may apply. Refer to member’s benefit plan.

CURRENT CODING:

CPT code:

REFERENCES:

1. Boyce JA, Assa'ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. Dec 2010; 126(6 Suppl): S1-58.
2. Buczylko K, Obarzanowski T, Rosiak K et al. Prevalence of food allergy and intolerance in children based on MAST CLA and ALCAT tests. Rocz Akad Med Bialymst 1995; 40(3):452-6.
3. Cell Sciences Systems. Alcat Test. n.d.; https://cellsciencesystems.com/patients/alcat-test/.
4. Gupta RS, Dyer AA, Jain N et al. Childhood food allergies: current diagnosis, treatment, and management strategies. Mayo Clin Proc 2013; 88(5):512-26.
5. IOM (Institute of Medicine). 2011. Clinical Practice Guidelines We Can Trust. Washington, DC: The National Academies Press.
6. Kaats GR, Pullin D, Parker LK. The short term efficacy of the ALCAT Test of food sensitivities to facilitate changes in bodycomposition and self-reported disease symptoms: a randomized controlled study. Bariatrician. 1996; Spring: 18-23.
7. Mylek D. ALCAT Test results in the treatment of respiratory and gastrointestinal symptoms, arthritis, skin and central nervous system. Rocz Akad Med Bialymst 1995; 40(3):625-9.
8. Solomon BA. The ALCAT Test - A guide and barometer in the therapy of environmental and food sensitivities. Environmental Medicine 1992; 9(2):1-6.

POLICY HISTORY:

Medical Policy Group, February 1999

Medical Policy Group, May 2004 (2)

Medical Policy Administration Committee, May 2004

Available for comment June 28-August 11, 2004

Medical Policy Group, May 2005 (1)

Medical Policy Group, May 2006 (1)

Medical Policy Group, May 2007 (1)

Medical Policy Group, May 2009 (1)

Medical Policy Group, May 2010

Medical Policy Group, May 2011 (3)

Medical Policy Group, September 2011 (1): Added CPT code 83516 to policy; no change in policy statement

Medical Policy Administration Committee, September 2011

Available for comment September 22 through November 7, 2011

Medical Policy Group, January 2013 (3): Updated Key Words; no change in policy statement

Medical Policy Panel, February 2014

Medical Policy Group, February 2014 (1): Update to Description, Key Points and References; no change to policy statement

Medical Policy Panel, February 2015

Medical Policy Group, February 2015 (3): 2015 Update to Key Points; no change in policy statement.

Medical Policy Panel, October 2017

Medical Policy Group, October 2017 (3): 2017 Updates to Title, Description & Key Points; no new References. Added “for all indications” to policy statement but no change in policy intent

Medical Policy Panel, October 2018

Medical Policy Group, October 2018 (9): 2018 Updates to Description, Key Points. No new references. No change to policy statement. Added key words: environmental illness, food intolerance, food allergy. Removed “ALCAT” from policy title to match association.

Medical Policy Panel, October 2019

Medical Policy Group, October 2019 (9): 2019 Updates to Description, Key Points. No new references. No change to policy statement.

Medical Policy Panel, October 2020

Medical Policy Group, October 2020 (9): 2020 Updates to Description, References. No change to policy statement.

Medical Policy Panel, October 2021

Medical Policy Group, October 2021 (9): 2021 Updates to Description, Key Points, References. Policy statement updated to remove “not medically necessary,” no change to policy intent.

Medical Policy Panel, October 2022

Medical Policy Group, October 2022 (9): 2022 Updates to Description, Key Points, References. Removed the word "cellular" from policy statement; No change to policy statement intent.

Medical Policy Panel, October 2023

Medical Policy Group, October 2023 (5): Updates to Description, Key Points, and Benefit Application. No change to Policy Statement.

Medical Policy Panel, October 2024

Medical Policy Group, October 2024 (5): Updates to Description, and Key Points. No change to Policy Statement.

This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.

This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.

Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.