Contributing factors to diagnostic error, representative examples
| Example | Contributing factor, category | Contributing factor, subcategory | Final diagnosis |
| A patient with severe autism spectrum disorder and communication difficulties presented to the emergency department with fever 3 days prior to the index admission and was discharged home. Blood cultures later grew Enterococcus spp, and the patient’s family was advised to return to the hospital but initially declined. After the patient ultimately presented, he was diagnosed with enterococcal bacteraemia due to choledocholithiasis and endocarditis in the setting of prolonged duration of untreated bacteraemia. | Access/presentation | Failure/delay in presentation | Endocarditis |
| A patient with end-stage renal disease on haemodialysis was treated with 6 weeks of intravenous ceftriaxone for Enterococcus endocarditis. She had prolonged altered mental status, though was noted to be more alert on days following haemodialysis. This was initially not appreciated by the care team. She was subsequently diagnosed with ceftriaxone-induced encephalopathy. | History | Suboptimal weighing of a critical piece of history data | Ceftriaxone-induced encephalopathy |
| A patient was initially admitted for generalised weakness and during this admission was noted to have persistent hypoxia that was attributed to aspiration or atelectasis; pulmonary embolism was considered but thought less likely. During the admission, the patient had clear lungs on exam with vital signs notable for hypoxia. On readmission, she re-presented with dyspnoea and was found to have bilateral pulmonary emboli. | Physical examination | Inaccurate/misinterpreted critical physical exam finding | Pulmonary embolism |
| A patient was admitted for traumatic fractures and found to have a pulmonary embolism for which he was anticoagulated. Patient’s haemoglobin decreased by 2.5 g/L during admission. This was attributed to haemodilution, though other cell lines did not decrease and the patient had received minimal fluid. He was readmitted with acute gastrointestinal bleeding from a gastric ulcer. | Tests (laboratory/radiology) | Erroneous clinician interpretation of test | Bleeding gastric ulcer |
| A patient’s blood cultures grew Staphylococcus aureus and Streptococcus anginosus. His admission chest X-ray showed a right lower lobe pulmonary infiltrate and a small right pleural effusion that was tracking into the minor fissure. He was readmitted with dyspnoea and hypoxia and found to have an empyema with pleural fluid cultures growing S. aureus. | Assessment | Failure/delay to recognise/weigh complications | Empyema |
| A patient presented with throat pain and fever. She was initially diagnosed with pharyngitis. Otolaryngologist was not consulted during index admission. She was readmitted with peritonsillar abscess requiring drainage. | Referral/consultation | Failure in ordering referral/calling consult | Peritonsillar abscess |
| A patient with a chronic indwelling Foley catheter presented with an abnormal urinalysis including pyuria and haematuria and was treated for urinary tract infection. Concomitant hypercalcaemia prompted team to order an outpatient referral to urology, but she was lost to follow-up. She was diagnosed with bladder cancer over a month later. | Follow-up | Failure/delay in timely follow-up/rechecking of patient | Bladder cancer |