Dr Sally Old, medico-legal advisor at the Medical Defence Union, said bad handwriting can also confuse other doctors.
The issue raised after an audit undertaken by the paediatric department at Birmingham Heartlands Hospital, which was published in the Archives of Disease in Childhood in November.
It found 479 different abbreviations were used in 168 sets of medical notes and a further 221 different abbreviations used in 25 shift handover sheets.
Only 15% of the abbreviations used appeared in the hospital’s intranet dictionary and only 17% appeared in a medical dictionary used by paediatric secretaries.
Sometimes abbreviations had multiple interpretations, for example ‘TOF’ meant either ‘tetralogy of Fallot’ or ‘tracheo-oesophageal fistula’.
Ms Old said: ‘The MDU advises doctors to use only the abbreviations or acronyms that are unambiguous and approved in their practice or hospital rather than inventing new ones that cannot be consistently applied.
‘For example, does ‘PID’ stand for Pelvic inflammatory disease’ or ‘prolapsed intervertebral disc?’