An unnamed family doctor has been reprimanded by the public health watchdog for failing to tell his patient about an abnormal test result.
The Health and Disability Commissioner says the man was later diagnosed with a form of cancer known as multiple myeloma.
The commissioner, Anthony Hill, says the 69-year-old man saw his doctor in 2009 for a skin rash.
The GP thought it was benign but referred him to a dermatologist, who removed a mole that was found to be the skin cancer melanoma.
The doctor apologised, but months later failed to tell the man about an abnormal result from blood tests that the man had requested.
The test indicated multiple myeloma in the patient, who left for an overseas trip during which he had to be hospitalised.
Anthony Hill says the failure to tell the patient about the significantly abnormal test result and to follow up on it was a severe departure from expected practice.
The commissioner says the doctor should have made better use of computer systems to help him properly manage the patient.
The GP had received the abnormal result and intended to tell the patient - but hit the wrong key on his keyboard, so the result went to a file where it was unnoticed.
Mr Hill says the doctor could have used other computer management systems available to doctors to remind him about the result, but didn't.
"This was not about a clinical judgement failure or a clinical competence failure, this was a good GP doing a good job and he intended to do the right thing. What he failed to do was use the system that he had available to him to make sure that, in fact, he delivered on that."
The doctor is no longer practising.