(Reuters Health) – Of nearly 90 mobile phone apps focusing on sexually transmitted infections (STIs), about a third had inaccurate and incomplete information in a recent study.

This significant variation in content, quality and medical advice could lead to sexual health risks for those who search for answers online before talking to a doctor.

“Due to the stigmatized nature of STIs, apps could be a great medium for providing accurate information to those most at risk,” said lead author Jo Gibbs of the University College London Department of Infection and Population Health in the UK.

“However, there is very little guidance available for the consumer to assess the accuracy and quality of information provided by apps, and to identify and distinguish those which are likely to provide legitimate, trustworthy content,” she told Reuters Health.

In September 2014, the research team looked on Google Play and iTunes for STI and genital infection apps that featured information about testing, diagnosis and treatment. They analyzed 87 apps to see if they met the 19 principles of the Health on the Net Foundation, which require health apps to include medical qualifications, confidentiality, cited facts and contact information.

The team also compared diagnosis and treatment information in the apps to what’s offered on the UK National Health Service’s STI website.

About 29 percent of apps met more than six Health on the Net criteria, and content varied widely. About 39 percent, or 34 of 87 apps, covered one or two infections such as gonorrhea and genital warts, and 46 percent covered multiple STIs. Five apps focused on STI testing in particular.

Importantly, 13 apps were fully accurate, 46 were mostly accurate and 28 were partially accurate, the researchers report in the journal Sexually Transmitted Infections.

Of the 87 apps examined, 25 contained more than one piece of potentially harmful information, for example, “certain medicinal herbs may also be beneficial in creating a strong immune response against HSV in non-infected partners,” or advice that getting treatment for genital warts will cause “a very bad time” and “will shatter your relationships.”

Apps that were available on both iOS and Android phones were more accurate than single-platform apps. In total, only one app provided completely accurate information about chlamydia, the most common STI in the UK. No apps contained documentation or citations.