Serum Compatibility Testing™—also called Dental Filling Compatibility or Blood Compatibility Testing—was devised by Hal A. Huggins, D.D.S., a dentist whose license was revoked in 1996 for gross negligence and other professional misconduct. Huggins falsely claimed that mercury-amalgam (“silver”) fillings were toxic, could cause chronic fatigue and many serious diseases, and should be replaced. The test is claimed to help select the safest replacement materials. The Administrative Law Judge who recommended the revocation concluded that Huggins had diagnosed “mercury toxicity” in all patients who consulted him in his office, even some without mercury fillings . A Huggins flyer  distributed in the mid 1990s advised:
|Don’t rush right out and have your silver-mercury fillings replaced just because you are tired of being tired. If you do, you may experience the “Frying Pan into the Fire Syndrome.” Since many alternative fillings contain other toxic ingredients, replacement of one toxic filling with another toxic filling is unhealthy, unwise, and expensive. It can lead to Re-replacement of your fillings.
Dental Compatibility Testing works like this. . .
—A sample of your blood is drawn and specially prepared.
—It is mixed with nearly a hundred dental chemicals that are included in over 1000 dental products to determine:
Talk to your dentist today to find out how to:
The leading provider of this type of test is now Scientific Health Solutions, of Colorado Springs, Colorado, whose director, Thomas Edward Levy, M.D., J.D., co-authored a book (Uninformed Consent: The Hidden Dangers in Dental Care) with Huggins that attacks amalgam fillings. Levy’s test—called Clifford Materials Reactivity Testing (CMRT)—is promoted with more subtle language such as, “The use of CMRT to help reduce materials-related risk on a patient-by-patient basis is a means by which the doctor can provide an increased measure of due diligence for individual patient welfare and a higher level of quality care to the patient.” 
The use of CMRT figured prominently in disciplinary action against Scott McAdoo, D.D.S., a fomer Huggins employee who was charged with professional misconduct  and in 2004 signed a consent agreement  under which he agreed to immediately stop doing the challenged procedures and to permanently surrender his dental license no later than February 12, 2005. The accusatory document, which refers to McAdoo as “Respondent,” stated:
|The dental material testing that Respondent “provides” is the Clifford Materials Reactivity Testing (“the Clifford test”) performed by Clifford Consulting and Research, Inc. (“Clifford”); on occasion, Respondent uses an identical test done by Huggins Diagnostic Center (“Huggins”). Respondent ordered dental material compatibility testing for the following 15 patients (14 had it done at Clifford and one had it done at Huggins). The test that both Clifford and Huggins perform is a serum compatibility test wherein a patient’s blood serum is mixed with a small amount of the material in question and observed for the formation of an immune complex which precipitates out of solution and collects at the bottom of the test well. The ALJ in Case Number DE 95-04 found the serum compatibility tests to be substandard and without clinical justification.
Upon completion of each patient’s test, Clifford (and Huggins) produced a report for Respondent. The report detailed groups of materials to which the patient had a “positive” immunological reaction (meaning the patient could be allergic and that the particular materials should not be used for a dental purpose in the patient’s mouth).
The report also listed approximately 3558 dental product which were either indicated or contraindicated for the patient, depending upon what group of materials the patient tested “positive” for.
Upon receipt of the test results, Respondent told these patients that he would eliminate identifiable materials that the patient was shown to react to immunologically by the compatibility test. Respondent further stated that he would restore the patients’ teeth using materials that the patient did not show a reaction to in the compatibility test. . . .
Respondent’s serum compatibility testing has no scientific basis to determine which materials will react with the immune system and which will not. Respondent’s serum compatibility testing is without clinical justification.
The need to test for dental materials reactivity, as an accepted or routine component of a comprehensive dental examination or as an accepted or routine component of determining a dental diagnosis or treatment plan, is not included in any accredited dental curriculum.
When an allergic reaction to a dental material is suspected or a systemic medical manifestation due to use of a dental material is suspected, the standard of care is to refer the patient for a medical consultation. Such testing and interpretation is the practice of medicine. Respondent failed to refer any of these patients for a medical consultation and/or interpretation of the test results.
Regardless of the actual compatibility test results. . . , Respondent used the same dental material to restore their teeth .
In 1990, the Arizona Dental Board censured Terry J. Lee, D.D.S., of Phoenix, Arizona for routinely advising patients to have their amalgam fillings replaced. The board’s order indicates that it objected to his reliance on Clifford testing, which it considered “not verified.” 
Why Serum Compatibility Testing Is Not Valid
The test is performed on a blood sample that is permitted to clot and then centrifuged to separate the clotted part from the serum . Small portions of serum are then put in wells in a test dish, and a “solution” of each dental material to be tested is added. If the resulting solution gets cloudy, the test is considered positive. The results are read with a densitometer, displayed as optical density readings, and tabulated in a 30-page report that recommends which materials are safest for replacing previous fillings and bridges. That way the patient can undergo new dental work—usually at very high prices—using only the recommended materials.
What really happens during “positive” reactions is that proteins are altered (denatured) and precipitate out of the solution. This resembles what happens when certain metal salts, reactive plastics, or other denaturing agents are added to egg white dissolved in water. The normally clear egg-white solution becomes cloudy as the protein precipitates. The same process occurs when serum proteins are heated or exposed to formaldehyde or many other agents. Huggins claimed that the test is not an allergy test but represents “actual immune surveillance of these products.”  However, nothing in the test actually shows any form of “compatibility” of the test substances with the person’s serum. Nor does the test have anything to do with immunity or the immune system. The “positive” reactions are nonspecific chemical reactions that have no practical significance. Qualified immunologists who have evaluated the test consider it absurd.
- Connick N. Before the State Board of Dental Examiners, State Board of Colorado. Case No. 95-04. In the matter of the disciplinary proceedings regarding the license to practice dentistry in the State of Colorado of Hal A. Huggins, D.D.S., License No. 3057. Feb 29, 1996.
- Safer dental fillings. Undated flyer distributed at a Huggins seminar in 1995.
- What Is CRMT? Scientific Health Solutions Web site, accessed November 11, 2005.
- Notice of duty to answer, notice to set, notice of hearing, notice of charges, and option to engage in alternative dispute resolution. In the matter of disciplinary proceedings regarding the license to practice dentistry in the state of Colorado of Scott R. Mcadoo, D.D.S., license no. 6394. Case No. DE 2003 – 008, filed in October 2003.
- Stipulation and final order. In the matter of disciplinary proceedings regarding the license to practice dentistry in the state of Colorado of Scott R. Mcadoo, D.D.S., license no. 6394. Case No. DE 2003 – 008. Signed in August 2004.
- Huggins HA. Serum compatibility testing: A revolutionary approach to selecting safer dental fillings (booklet). Colorado Springs, CO: Huggins Diagnostic Laboratory, Sept 15, 1989.
- Board order. In the matter of Dr. Terry J. Lee. Before the Arizona Board of Dental Examiners, Complaint Numbers 89170 and 89172, April 25, 1990.
- Huggins HA. PAR: Proper amalgam removal (booklet). Colorado Springs, CO: Huggins Diagnostic Center, Jan 1, 1993.
Dr. Baratz, who practices in Braintree, Massachusetts. has extensive training and practical experience in internal medicine, emergency medicine, oral medicine, dentistry, material science, and research methodology. He also serves as a medical and dental consultant to many state licensing boards, federal agencies, insurance companies, and the legal profession.
This article was revised on November 11, 2005.