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Antigen Leukocyte Antibody Test

Policy Number: MP-165

Latest Review Date: October 2020

Category: Laboratory

Policy Grade: C


Antigen Leukocyte Cellular Antibody Test (ALCAT) is considered not medically necessary and investigational for all indications.


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.

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 have intolerance. It is not intended to diagnose food allergy. 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 70 to 357.


The most recent literature review was performed through July 20, 2020.

Summary of Evidence

For individuals who have a suspected intolerance of environmental agents or food who receive the ALCAT, the evidence includes a randomized controlled trial (RCT) and case series. The relevant outcomes are morbid events and medication use. There is a lack of published research on the diagnostic accuracy of the ALCAT test; 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 improvement in outcomes following use of ALCAT, but it is not possible to determine whether these changes occur as a result of test itself, bias, variation in the natural history of the condition, and/or the placebo effect. The evidence is insufficient to determine the effects of the technology on health outcomes.

Practice Guidelines and Position Statements

No clinical practice guidelines were identified on the diagnosis and management of food intolerance.

The National Institute of Allergy and Infectious Disease (NIAID) published guidelines on the diagnosis and management of food allergy in 2010. These guidelines defined and distinguished food intolerance from food allergy, but did not provide recommendations for the diagnosis and management of intolerance. For the diagnosis of food allergy, the guidelines stated that “tests selected to evaluate food allergy should be based on the patient’s medical history and not comprise large general panels of food allergens."

U.S. Preventive Services Task Force Recommendations

Not applicable.


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


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 (CLIA). The ALCAT is available under the auspices of the Clinical Laboratory Improvement Amendments (CLIA). Laboratories that offer laboratory-developed tests must be licensed by the Clinical Laboratory Improvement Amendments (CLIA) for high-complexity testing. To date, the U.S. Food and Drug Administration (FDA) has chosen not to require any regulatory review of this test.


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

ITS: Home Policy provisions apply

FEP contracts: FEP does not consider investigational if FDA approved and will be reviewed for medical necessity.


CPT code:


Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, multiple step method


Unlisted immunology procedure


  1. ALCAT test website. Available online at:
  2. American Academy of Allergy Asthma and Immunology. AAAAI Work Group Report: Current approach to the diagnosis and management of adverse reactions to foods. October 2003.
  3. 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.
  4. 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.
  5. Cell Sciences Systems. Alcat Test. n.d.; Accessed July 25, 2020.
  6. 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.
  7. Kaats GR PD, Parker LK. The Short Term Efficacy of the ALCAT Test of Food Sensitivities to Facilitate Changes in Body Composition and Self-reported Disease Symptoms: A Randomized Controlled Study. The Bariatrician 1996; Spring: 18-23.
  8. 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.
  9. NIAID-Sponsored Expert Panel, Boyce JA, Assa'ad A 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 2010; 126(6 Suppl):S1-58.
  10. Solomon B.A. The ALCAT Test - A guide and barometer in the therapy of environmental and food sensitivities. Environmental Medicine 1992; 9(2):1-6.
  11. Wüthrich B. Unproven techniques in allergy diagnosis. J Investig Allergol Clin Immunol 2005; 15(2): 86-90.


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 Group, October 2020 (9): 2020 Updates to Description, References. 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.