2006 was the year when the use of biomarkers and genetic testing to indicate the presence of disease or disease predisposition, based on the sort of research results described above, began to take off. Genetic testing and biomarker identification was a $5 billion business in 2006 and growing by 25 percent annually. Insurers did not rush to pay for the tests, though some test makers got a foot in the reimbursement door.

The tests also have a foot in the door among practitioners who do not conform to the conservative norm discussed in the Barriers section. One of them, Mayo Clinic chairman of psychiatry and psychology David Mrazek, told a reporter he does pharmacogenetic testing “very regularly,” especially for children (who are particularly vulnerable to drug side effects) and for patients with a personal or family history of adverse drug reactions. Mrazek was convinced of the value of genetic testing for enzyme problems. “Before I would put any child” on a drug metabolized by the 2D6 enzyme, he said, “I would want to know that they have at least one good copy of the 2D6 gene. . . . I’ve been very surprised by some very senior psychiatrists saying, ‘I don’t need this; I’ve been prescribing Prozac for years.’ Young clinicians are very quick to say, ‘Gee, here’s a tool that can potentially prevent a tragic event.’ ”

Tests available in 2006 included:

• A test that predicts side effects from colon-cancer drug irinotecan. FDA approved, commercially available. 

   

• A test that predicts benefit from breast-cancer drug tamoxifen. Commercially available but needed further validation. 

   

• Tests for two different genetic variations that predict best dose of the blood-thinner warfarin. 

   

• A test to tell whether a woman with a certain kind of breast tumor might not benefit from chemotherapy and to predict the likelihood of a relapse. 

   

• A $3,000 blood test that analyzes whether a transplanted heart is being rejected. 

   

• A $3,000 test for the risk of developing breast cancer. 

   

• Up-to-$1,460 tests to determine the best drugs regimen for HIV/AIDS patients (at that price, unfortunately, it won’t make much difference where it is needed most.) 

   

• A $500 DNA test for colon cancer. 

   

• A $1,000 test to predict whether a patient with hepatitis C will develop cirrhosis of the liver, and therefore who is most in need of immediate treatment and who can wait. 

   

• A breast cancer gene test that was 80 percent accurate in predicting the optimum chemotherapy regimen for individual cancer patients in early trials. 

These were tests intended for hospitals and doctors to perform, but do-it-yourself tests were also in evidence in 2006, notwithstanding advice from the American College of Medical Genetics in 2004 for the public to avoid them. In May 2006, Good Housekeeping magazine was proclaiming that ordering genetic tests by mail was “as simple as ordering takeout.” Mail-order tests available in 2006 included tests for hereditary hemochromatosis ($199) and BRCA genes associated with breast and ovarian cancer ($3,300, with some restrictions). One company offered tests for a problem on one gene for $250, or a battery of tests on four genes for $800, and four US retailers began testing over-the-counter sales of $99.99 home test kits for bone health, heart health, insulin resistance, inflammation and antioxidant/detoxification.

The technology of testing itself also advanced in 2006. One company began to commercialize a test platform that eliminates the need for polymerase chain reaction (PCR) processing, simplifying genetic testing and eliminating the need for sophisticated labor, cost-prohibitive instrumentation, and dedicated lab space. The company claims it will “decentralize” molecular testing from a few sophisticated academic laboratories to the point of care, by enabling broader access to genetic testing technology.