An IT error meant a number of results for blood and other medical tests handled by the County Durham and Darlington (CD&D) NHS Trust took months to be returned to the GPs who ordered them.
The trust has admitted that an error in the IT system used to share pathology results with GPs meant they were not sighted on those results. However the trust said all results were "analysed and reported appropriately" by specialists.
Hospital bosses said staff were now working closely with GP practices in the area to ensure they "now receive and where needed review" those results. The trust has not disclosed how many patients are effected - instead saying this was a "small number" of results.