The Scottish Ambulance Service has rejected complaints that its call handling system fails effectively to prioritise emergencies.
Reports that serious incidents such as heart attacks are being logged as non-priorities, while less critical illnesses receive red alert treatment, were catalogued in the Scottish press this week.
A spokesman for the Scottish Ambulance Service insisted that there is no evidence to back up the anecdotal complaints, but said that it is investigating the accusations.
"This is a non-story," he said. "We have no proof of what people are saying and we think the claims are unfounded."
Emergency calls are handled by the Automated Medical Priority Dispatch System (AMPDS), an off-the-shelf application that is already in use across England and Wales.
The £13m system was introduced into the Lothian and Borders region of Scotland in August 2002, and will be rolled out across the whole of Scotland at a later date.
Life-threatening conditions receive top priority, resulting in an ambulance response time of less than eight minutes.
Non-life threatening, but still serious, complaints should be dealt with in 14-19 minutes, with lower priority calls redirected to another department.
Paul Goss, a director at healthcare IT analyst Silicon Bridge Research, said: "There are a number of factors that can affect a system like this. It is possible that the weightings and characteristics within the system are not balanced correctly."
But he pointed out that the system is dependent on the quality of information given by the caller and its interpretation at the call centre.
Chris Hartley-Sharpe, senior operations officer at the London Ambulance Service, has used AMPDS since November 2000 and agrees with Goss.
"AMPDS offers questions to call centre staff and assigns a determinant code based on the answers," he explained.
"The call handlers still have to make a number of judgements on which set of questions to ask and how to get the best information possible."
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