The Flaw in Cytotoxic Testing:
There's No Proof It Works

Richard C. Thompson

Cytotoxic testing is touted as a way of tracking down and curing ills by on-the-spot testing of blood for food allergies. While the idea may sound plausible, there is no proof it works.

Yet such testing has been highly promoted. The promotions began in 1983 with newspaper ads that invited investors to get into the "profitable field" of allergy testing.

For an investment of about $30,000 the promoters supply test kits and training and show the investor how to operate an allergy clinic. The investor purchases the kits, chooses the location, and provides clinic staff.

Ads like the one shown to the right were run in national newspapers, among them The Wall Street Journal. The ads said investors could get rich using "a scientific breakthrough that charts 245 food allergies simply and efficiently." Within weeks, storefront clinics began appearing around the country and FDA began receiving inquiries from the news media, consumers and health professionals.

But these ads to investors—and later ads by the operators themselves—misrepresent the nature of cytotoxic testing. It is not an accepted clinical procedure, and the significance of the test results, if any, has not been established.

The promoters also claim that only a business permit is required to operate a clinic and that cytotoxic testing is "nutritional analysis" and not subject to federal or state regulation. But they are mistaken. The food extracts used are biologics licensed by FDA; thus they are prescription drugs that can be ordered only by a physician. Using them in a blood test gives FDA added jurisdiction under medical device laws. And the clinics themselves may require licensing by state of local health authorities.

In cytotoxic testing, about 10 cubic centimeters (one test tube) of blood are taken from the patient. The white cells (leukocytes) are mixed with plasma and sterile water and placed on microscope slides, after each slide has been coated with the dried extract of a particular food. There are generally 200 slides representing 200 different foods. The reaction of the cells to the extracts is examined under a microscope. If the cells collapse, disintegrate or change shape (or the person examining them says they do), the patient is supposedly allergic to that particular food.

This evidence of food allergy is then used to explain a variety of symptoms patients may have or think they have. To correct this condition the clinic typically offers a "personalized diet program," devised by the clinic operator, that includes vitamins and minerals the clinic has for sale. Investors are told they should make even more money on these products than they do for the testing itself.

The claims made by operators of the clinics are not modest.

Cytotoxic testing will, says one, deliver you from asthma and arthritis; from canker sores, chronic cough and confusion; from diarrhea and depression; from heart palpitations and headaches; in fact, from 27 flaws in the human condition.


This is part of a full-page ad that appeared
in the New York Times on July 14, 1984.

It can, says another, protect you against "the disasters linked to the food you eat . . . ."

A third claim is simplicity itself; "Feeling bad? Try cytotoxic testing."

The list of conditions that promoters claim are related to food allergy also includes anxiety and acne; baldness, back pain and bedwetting; constipation, crying and conjunctivitis; eczema and fatigue; hearing loss; insomnia; learning disorders; obesity; rashes; and stomachache, stress and water retention

Don't believe it. The FDA, the National Institutes of Health, and the American Academy of Allergy and Immunology say there's no evidence it works.

The procedure is also known as Bryan's test, leukocyte antigen testing, and food sensitivity testing. But, by whatever name it is called, there's no evidence as yet that it tests for food allergies. There have been no controlled experiments showing that white cells shrink, shrivel and die when exposed to food substances to which a person is allergic. Until there are, the academy and the National Institute of Allergy and Infectious Diseases say cytotoxic testing "must be considered an experimental procedure" with no clinical uses.

The usual patient-doctor relationship doesn't exist in cytotoxic testing. Patients apparently are not seen or examined by a physician, yet use of allergenic extracts can be legally ordered only by a medical doctor.

There is also the question of whether clinic personnel are qualified to assess symptoms, read the microscope slide, and offer nutritional guidance. A technician takes blood from the patient, and lab personnel apply it to the slides. The results may be interpreted by a "nutritional counselor" working on commission who will then note the vitamins and minerals—available right there or next door—that the patient will need to correct this "allergic condition."

Cytotoxic testing is expensive, costing from $200 to $400 for the usual series, plus additional charges for the vitamins. Although ads imply this is covered by health insurance, the clinics require that the patients pay and then be reimbursed. Medical insurers are questioning the procedure, and the Health Care Financing Administration that funds Medicare intends to exclude cytotoxic testing from its coverage. HCFA says such testing "lacks evidence of clinical effectiveness and has no scientific rationale."

There are some 1,200 extracts of various substances prepared by licensed suppliers and approved by FDA for allergy skin tests. About one-fourth are food extracts, labeled and intended for certain uses. Cytotoxic testing is not one of those uses, and no manufacturer of these extracts has requested FDA approval to market for such use. Some clinics may be preparing their own food extracts or obtaining them from sources within the state where they are used, which makes them less readily subject to FDA regulation.

FDA is investigating cytotoxic clinics and promotions, which seem designed to operate outside the traditional practice of medicine. Meanwhile, the agency advises persons who believe they may have a food allergy to see a properly trained physician for a complete medical history, physical examination, and thorough diagnosis and proven treatment.


This article is reprinted from the the October 1984 issue of FDA Consumer. Mr. Thompson was a member of the FDA's publications staff.

This page was posted on August 11, 2007.

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