HUNDREDS of patients have been put at risk after a computer glitch caused parts of their medical notes to disappear and attach to other patients' records.
Scotland on Sunday can reveal the error was caused by faulty software in the controversial GPASS computer system used by more than 80% of GPs in Scotland.
It meant text longer than 255 characters entered by doctors into a patient's medical record would disappear, causing potentially vital clinical information to go missing.
It is believed the error may have been affecting patients' records for up to four years before it was spotted. In some circumstances the missing text re-attached itself to another patients' medical records.
Officials at the National Services Scotland, which operates the system, found a solution for the problem last October. But furious doctors have warned patients may have unknowingly received potentially harmful treatment or drugs intended for someone else.
A letter sent to GPs highlighted the problem. It stated: "When you look at the encounter [entry] for the patient, the text truncates after the 255th character and the remainder of the entry is not visible.
"In very rare circumstances, the missing text can appear to re-attach itself to another patient's record. This is a very unusual occurrence."
GPASS is used by more than 904 GP practices across Scotland. The fault is believed to have affected mainly those operating "paper-light" systems, where doctors enter notes from consultations directly into the computer, meaning there is no paper back-up. There are believed to be around 100 paper-light practices in Scotland, each with thousands of patients.
Doctors claim this is not the first problem with the latest edition of the computer system, which has been in use in Scotland since April 2001.
Shortly after it was introduced, two patients in Glasgow were given the wrong prescriptions because of a printing error caused by the system.
In one case, a 90-year-old woman was given a prescription which her doctor said could have been fatal had the patient not spotted the mistake.
Last night one GP, who asked not to be named, said: "There have been endless problems with this computer system. This latest one was potentially highly dangerous as important information about a patient's medication or condition might have been cut out and given to another patient."
Dr Michael Hendry, a member of the GPASS User Group, said a number of doctors were concerned about the safety of the system. He said: "This latest error had been a problem for practices that do not use paper notes and record everything on screen. I believe a small number of practices were affected, but a fix for the problem has now been sent out to all practices."
A spokeswoman for National Services Scotland said "a small number" of practices had been affected as most still used paper notes. She added: "No information was actually lost and a fix has now been issued that re-attaches the missing data."
The Scottish Executive has encouraged GPs to use computer systems as it attempts to modernise the NHS with electronic patient records.
SNP shadow health minister Shona Robison said: "The Executive needs to ensure the monitoring of GPASS and other electronic records are robust and pick up faults before they can do any harm."