Image caption The $99 personal DNA test detects a range of gene variants

US genetic testing firm 23andMe, which is backed by Google, has stopped marketing its at-home kit, a company spokeswoman has said.

It halted television, radio and online advertising for its $99 (£60) personal genome analysis product last week.

The move follows a warning letter filed by the US Food and Drug Administration (FDA) last month.

The spit test is supposed to provide details about a person's health risks based on gene variants they carry.

The FDA ordered 23andMe to "immediately discontinue" its Saliva Collection Kit and Personal Genome Service (PGS) because it had failed to provide adequate information to support the claims made in the company's marketing.

In a blog post last week, the company's co-founder Anne Wojcicki responded to the FDA letter.

"We have worked extensively with our lab partner to make sure that the results we return are accurate," she wrote.

"We stand behind the data that we return to customers - but we recognize that the FDA needs to be convinced of the quality of our data as well."

She said 23andMe had been speaking to the FDA since 2008 and had submitted an application for clearance in July 2012, following on with another submission in August.

Ms Wojcicki added: "This is new territory for both 23andMe and the FDA. This makes the regulatory process with the FDA important because the work we are doing with the agency will help lay the groundwork for what other companies in this new industry do in the future."

The FDA said it was particularly concerned about the potential health consequences of false positive or false negative assessments by the PGS for genetic risk related to breast cancer and to adverse drug responses.

It said consumers might make important health decisions based on inaccurate information. Likewise, a false negative could result in a failure to recognise and act on an actual risk.

In September, 23andMe said that the number of people in its genetic database had reached 400,000 people, and the kits could still be purchased on its website.

The embattled firm, based in Mountain View, has also been hit with a class action lawsuit filed in California, which alleges there is "no analytical or clinical validation for the PGS for its advertised uses".