Poor connectivity is hampering efforts in the NHS to exploit mobile technology that, if done properly, could deliver annual savings of at least £3,000 per doctor.
The Department for Health has been running a test called the National Mobile Health Worker, but the warning comes from a new report on the project that says unreliable signals are a major barrier to the adoption of mobile devices in the NHS.
Mobile healthcare projects must be willing to experiment with different network providers to find the best coverage for users, the document says.
And although the report sees some financial benefits from giving doctors mobile technology, they are by no means the same in every case, it argues.
In response, more network-based applications need to be developed so that mobile devices are able to store data so that users can continue working even when they cannot get a signal.
Overall, users like mobile technology and their productivity increased in most of the eleven sites taking part in the trial. In addition, more time was spent with patients after mobile devices were implemented.
The project began in 2010 and will run until 2012 and is led by a team from the Department of Health's community information project plus suppliers Panasonic and BT Healthcare.
The £3,000 savings figure was calculated from the costs involved in reducing the number of referrals, hospital admissions and visits that clinicians made with the help of mobile devices.