A personal genetics startup thinks that there is one set of DNA variants that everyone should know: the ones that help determine how you respond to drugs.

Genome Liberty, a New Jersey-based startup, wants to provide a $99 test that will tell customers, based on their genetics, if they should take a nonstandard dose of a drug because their body will break it down faster or slower than most people. In some cases the test might suggest a particular drug someone should take or avoid. “The idea is to give you a card to keep in your wallet, or an iPhone app, which says which medications you shouldn’t take,” says cofounder Jeffrey Rosenfeld, a genome scientist at Rutgers University.

The company would offer these tests directly to consumers, who could then relay any relevant information to their doctors, Rosenfeld says.

Genome Liberty isn’t the first company to offer such tests. The consumer genetics company 23andMe also offers some drug response tests in its genome scan, which also includes tests for things like eye color and the genetic risk for developing serious diseases. Rosenfeld says Genome Liberty wanted a more focused test. “The idea is to provide information that is usable, that you can act on,” he says.

Consumers who get the Genome Liberty drug response test would send a sample of saliva to the company’s lab. The company scans the genome for DNA variations in 11 liver enzyme genes, which are a subset of the dozens of genes encoding enzymes for drug metabolism. Enzymes in the liver process drugs and can either deactivate or activate drugs, depending on the compound. Different people carry different versions or amounts of many of these enzymes, which can affect how they respond to drugs. Some patients may process a drug more quickly, more slowly, or perhaps not at all.

Genome Liberty says that variants in those 11 enzymes can affect the activity of nearly 80 drugs in the body. The test “will tell people which medications they should take and which they should avoid based on markers in their DNA,” says Rosenfeld.

The company is using a crowdfunding site to raise money to develop its test, which is available for pre-order. The recent U.S. Supreme Court decision that limited the patent claims that companies can make on genes (see “U.S. Supreme Court Says ‘Natural’ Human Genes May Not Be Patented”) helped spur Genome Liberty to launch. “We were worried about whether we could start this company or not,” says Rosenfeld. Until that decision, he says, most genes were covered by a patent.

It is still not clear whether genetic tests sold directly to consumers will come under regulatory scrutiny. In 2010, the FDA warned 23andMe and other consumer genetics companies that their services amount to medical devices and thus need regulatory approval. But since then, the U.S. government has not come up with clear rules for these companies. Nevertheless, 23andMe applied for regulatory approval for portions of its test last year (see “Personal Genetics Company Seeks Regulatory Approval”).

Another question is whether doctors will make use of information from a consumer genetics test. Physicians don’t always trust the results of direct-to-consumer tests and may not have clear medical guidelines for how to use it (see “Why We Have a Right to Consumer Genetics”). But the connections between the liver enzyme variants and drug response are well-supported, says Rosenfeld. If a doctor doesn’t want to accept these results, he says, then “find a different doctor.”