10 new genetic tests available each day, US study finds

Every day, about 10 new genetic tests come to market in the USA, a study has found. 

In total, there are already about 75,000 tests available – and those are just the ones that can be ordered by doctors, not genetic tests marketed directly to consumers. 

When it comes to doctors selecting which tests to order, the huge numbers available make this field something of a 'Wild West, because we have so many tests out there', study author Professor Kathryn Phillips at the University of California San Francisco told The Washington Post. 'Trying to sort out what to use, when and how much to pay for a test is pretty complicated.'

The researchers analysed data on test availability in the USA and private insurer spending on them from 2014 to 2017, with a particular focus on tests that analyse multiple genes. They found that prenatal tests resulted in the highest spending, followed by tests for hereditary cancers. In addition, of the 75,000 tests discovered, only about 10,000 were unique test types, working in a distinct way from the others. 

'Ten new tests a day - no one can be expected to master that,' Diane Hauser of the Institute for Family Health in New York told The Washington Post. In another recent study, she and her colleagues found that most primary-care providers in New York City did not feel confident interpreting genetic test results for chronic diseases and lacked trust in the companies offering these tests. Many doctors were also concerned that genetic testing might lead to insurance discrimination. 

Since the human genome was mapped in 2003, the market in genetic tests has grown rapidly. Genetic tests for paediatric and rare diseases appear to be growing the fastest, followed by prenatal, cancer, haematology and neurology tests.

In addition to doctors' problems in seeking out the most appropriate test, the sheer number on offer also raises issues of access and regulation. Availability varies depending on where a patient lives in the USA, what insurance they have, and on the nature of the test. Those developed in the laboratory are not regulated by the US FDA (Food and Drug Administration). Lastly, many patients may be asked to pay out-of-pocket for the tests. 

The study was published in the journal Health Affairs.