IT issues have led to the postponement of some hospital appointments and surgery at Leeds hospitals.
It is not known how many patients are affected by the IT gremlins but Leeds General Infirmary, St James's, Chapel Allerton, Wharfedale and Seacroft hospitals are all reporting issues.
It is understood that Leeds Teaching Hospitals Trust had been "experiencing some significant problems with the pathology IT system".
A spokesman advised that “If patients are worried they should contact their outpatient clinic, clinician or GP.”

Controversial 500MW Solar Farm Spanning Milton Keynes and Northamptonshire Approved Despite Environmental Concerns
Nine People Charged with 49 Offences Following Major Police Raids in Rochdale
Calderdale Youth Justice Service Praised for Supporting Young People Despite Inspection Rating
Bradford Driver Jailed After Ramming Police Car in Huddersfield
Labour Loses Control of Hounslow Council After Councillor Charged with Fraud
Manchester Communities Invited to Apply for Remembrance Sunday Grants
Keighley Women and Children’s Centre Completes Major Expansion
Milton Keynes Man Convicted of Daesh-Related Terrorism Offences
Leeds Bradford Airport Workers Announce 48-Hour Strike
Bradford Youngsters to Mark World Food Day with Cookery Challenge
Four Men Charged Following Series of Warrants in Rochdale
Legal Show
Alim OnAir
Remix Saturdays
Bhangra Nights