Stay Away from Cytotoxic Testing

Stephen Barrett, M.D.

Cytotoxic testing—also called Bryan's test, the Metabolic Intolerance Test, or sensitivity testing—was promoted during the early 1980s by storefront clinics, laboratories, nutrition consultants, chiropractors, and medical doctors. Advocates claimed it could determine sensitivity to food, which they blamed for acne, anxiety, arthritis, asthma, back pain, baldness, bedwetting, conjunctivitis, constipation, depression, diarrhea, eczema, excessive sweating, fatigue, headaches, hearing loss, hoarseness, hypertension, hyperactivity, insomnia, learning disorders, nosebleeds, obesity, rashes, sinus trouble, stomach disorders, susceptibility to cancer, and other problems.

To perform the test, about 10 cubic centimeters of a patient's blood were placed in a test tube and centrifuged to separate the white cells (leukocytes). These were mixed with plasma and sterile water and applied to a large number of microscope slides, each of which had been coated with a dried food extract like that used by allergists for skin testing. The cells were then examined under a microscope at various intervals over a two-hour period to see whether they had changed their shape or disintegrated-supposedly signs of allergy to the particular food. Typically, the test results are used to explain the patient's symptoms and to design a "personalized diet program" that includes vitamins and minerals-sold by those administering the test.

The most blatant promotion was that of Bio-Health Centers of Huntington Beach, California, which charged $350 to test for 186 common foods and additives. One of its ads—headlined "DISASTER LINKED TO THE FOOD YOU EAT!"—claimed that "if you currently suffer from any health difficulties, this test is worth taking." A brochure from the company suggested that cytotoxic testing could help solve the problems of overweight, headaches, stomach and intestinal problems, depression, stress, confusion, sinus problems, asthma, arthritis and hypoglycemia. Bio-Health Center teams composed of a "nutritionist" and a nurse traveled around the country, holding evening meetings during which they couldservice about 30 people per night—for a gross intake of about $10,000. Clients were told that after their test results arrived, they could call the lab's toll-free number as often as needed for further dietary advice. Testing could also be obtained by mailing a blood specimen to the lab.

One Bio-Health Centers program was attended by Raymond G. Slavin, M.D., AAAI's immediate past-president, and his wife, Alberta. After slides were shown, a lecture was given by a young man who said he had undergone two years of special nutrition training. Among other things, he advised the assembled group that inhalant sensitivities are not important—so that someone allergic to cats would no longer have this problem if offending foods are no longer eaten. Mrs. Slavin actually had no allergies. But her test report, which arrived three weeks later, said that she was allergic to 25 foods—including wheat, cane sugar, corn, potato, beef and milk—and should avoid all of them for an 8-week period.

Severe Criticism

The American Academy of Allergy, Asthma and Immunology (AAAAI), the nation's largest group of allergists, has concluded that cytotoxic testing is ineffective for diagnosing food or inhalant allergies [1]. Its position paper noted:

Critical statements have also been issued by the American Academy of Otolaryngology-Head and Neck Surgery, the New York Academy of Medicine [6], the Royal College of Physicians [7], and even the American Chiropractic Association [8].

Government Actions

In the mid-1980s, investigators from the FDA and the New York health department mailed two blood samples to Bio-Health Centers. The first specimen was from a physician who had no allergies or health problems. The second was blood from a cow. In both cases, the lab reported allergies to a large number of foods [9]. In 1985, the attorneys general of New York and California subsequently obtained restraining orders against this lab, and the attorney general of Washington obtained one against another lab. During the same year, the Pennsylvania Department of Health's Bureau of Laboratories banned cytotoxic testing within Pennsylvania and stated that any laboratory caught doing the test would have its permit revoked [10].

In 1985, the Health Care Financing Administration (HCFA), which administers Medicare, determined that cytotoxic testing be excluded from Medicare coverage. HCFA had proposed this policy in 1983 because the test "lacks an acceptable rationale" and does not correlate with clinical evidence of food allergy [11].

That same year, the FDA issued a Compliance Policy Guide stating that cytotoxic testing kits could not be legally marketed without FDA approval and that the agency would consider regulatory action if violative test kits were marketed [12].

These actions greatly stopped the blatant marketing of cytotoxic testing, but some practitioners still use the test. If you encounter a practitioner who claims that testing blood preparations with large number of food extracts is a useful diagnostic procedure, avoid further contact with that practitioner and report the matter to state licensing authorities.


  1. American Academy of Allergy: Position statements—Controversial techniques. Journal of Allergy and Clinical Immunology 67:333-338, 1980. Reaffirmed in 1984.
  2. Chambers VV and others. A study of the reactions of human polymorphonuclear leukocytes to various antigens. Journal of Allergy 29:93-102, 1958.
  3. Lieberman P and others. Controlled study of the cytotoxic food test. JAMA 231:728, 1974.
  4. Benson TE, Arkins JA. Cytotoxic testing for food allergy: Evaluations of reproducibility and correlation. Journal of Allergy and Clinical Immunology 58:471-476, 1976.
  5. Lehman CW. The leukocytic food allergy test: A study of its reliability and reproducibility. Effect of diet and sublingual food drops on this test. A double-blind study of sublingual provocative food testing: A study of its efficacy. Annals of Allergy 45:150-158, 1980.
  6. New York Academy of Medicine Committee on Public Health. Statement on cytotoxic testing for food allergy (Bryan's test). Bulletin of the New York Academy of Medicine 64:117-119, 1988.
  7. Lessof MH and others. Food intolerance and food aversion. A joint report of the Royal College of Physicians and the British Nutrition Foundation. Journal of the Royal College of Physicians of London 18(2), April 1984.
  8. Saywer CE, Adams AH. The cytotoxic leukocyte test. A position statement of the ACA Council on Nutrition. ACA Journal of Chiropractic 21(2):59-61, 1987.
  9. Hecht A: Lab warns cow: Don't drink your milk. FDA Consumer 19(6):31-32, 1985.
  10. Bartola J: Cytotoxic test for allergies banned in state. Pennsylvania Medicine 88:30, Oct 1985.
  11. Proposed notice: Medicare program; Exclusion from Medicare coverage of certain food allergy tests and treatments. Federal Register 48(162):37716-37718, 1983.
  12. Cytotoxic testing for allergic diseases. FDA Compliance Policy Guide 7124.27, March 19, 1985. Revised March 1995.

This article was revised on April 9, 2002.

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