Doctors need guidance on how to avoid problems when using the latest telecommunications technology to reach patients, says a researcher.
Patients can be more easily reached
Dr Hilary Pinnock, a GP from Edinburgh, said everything from consultations with patients on mobiles, to hi-tech 'telecare' projects should be covered.
She said doctors may be legally vulnerable if confidential data goes astray, or a misdiagnosis is made.
The warning features in the journal Quality and Safety in Healthcare.
However, experts point out that most systems now use heavily encrypted information.
Last week, the government announced £12 million of investment in three schemes to monitor people with long-term conditions such as high blood pressure and diabetes in their homes electronically, then transmit the information back to doctors via mobile phone networks.
It is seen as one way of reducing the number of hospital stays for people with chronic problems.
Some hospitals transmit hospital appointment reminders by text message, with a few doctors even using this method to pass test results back to patients.
Dr Pinnock, from Edinburgh, said that while there is great potential for improving the service to patients, doctors need to know that mobile phone communication has the same legal status as older forms of contacting patients.
She said: "As a GP, I often arrange a phone consultation with a patient on their mobile phone, and they'll answer it, and it's obvious from the noise in the background that they're on a bus.
"I need some advice on whether this is appropriate practice."
She pointed out that confidential information sent to a mobile can get into the wrong hands if the mobile is lost or stolen, and that doctors may not be legally covered if they make an incorrect diagnosis using a picture taken on a mobile phone.
There have been several projects which rely on mobile phone pictures to aid doctors, including one in Dunfermline which uses pictures of road traffic accidents sent to A&E doctors to prepare for the arrival of casualties.
Professor Lionel Tarassenko, from the University of Oxford, has been involved in projects which use monitoring equipment linked to mobile phones to help asthmatics and diabetics.
In the diabetes study, a blood glucose monitor was linked, using a Bluetooth adapter, to a mobile phone, with the read-out transmitted to a central server.
The patient's practice nurse was given a password to gain access to the confidential information.
He said: "There should be no concerns over security. The mobile phone message has 64-bit encryption, of the same standard used by the MOD - if it's good enough for them, it should be good enough for us.
"A conversation with your doctor over a landline is far less secure. If you are using old technology such as SMS text messaging, that is also less secure."
A spokesman for the Department of Health said no guidance was currently planned, and that doctors should use their own judgement on whether to use mobile communication to help their patients.
"I wouldn't expect doctors to do anything they felt was inappropriate," she added.