An investigation found the elderly woman had gone to her GP six times in 19 days and was vomiting and refusing food.
Blood tests were delayed until the day before she was rushed to Hairmyres Hospital by her concerned family.
On the day she was admitted, her doctor was on his way to her house to tell her she had kidney failure.
She died a few days later after being transferred to Monklands Hospital for emergency dialysis.
The surgery, in Lanarkshire, has been ordered to apologise to the family for "unacceptable" standards of care.
Staff at the hospital were said to be "surprised" that the woman had not been admitted sooner.
On one home visit by a GP she was vomiting blood but was not admitted to hospital or referred for further tests.
The GP practice has been ordered to carry out a significant case review, following an investigation by Scottish Public Services Ombudsman, Jim Martin.
He described the clinical examination and assessment of Mrs A's condition by doctors on two separate occasions as "unacceptable" and said the surgery had delayed urgent blood tests.
A report found a GP had gone to see the woman the day before she was taken to hospital and was not concerned enough to admit her.
The following day her son found her wandering around the house in a confused state and took her to Hairmyres Hospital.
She was transferred to Monklands Hospital for emergency dialysis but died a week later on November 2, 2011.
Mr Martin said: "There were serious, unaddressed failings on the part of the practice.
"The clinical examination and assessment of Mrs A by doctors from the practice on two separate occasions was also of an unacceptable standard."
"Overall Mrs A's care had lacked focus. The practice had not taken a proactive approach to the situation, nor had they managed Mrs A's care and treatment reasonably.
"Mrs A's family had to repeatedly request assessments for Mrs A, but their concerns and opinion of her condition had not been given adequate consideration.
"The practice had not taken account of the multiple medical conditions that Mrs A suffered from and had failed to request blood tests timeously."
"The practice should now apologise sincerely to Mrs A's family for failures identified in her care and treatment."
The surgery said lessons had been learned from the incident.