The Scottish Public Services Ombudsman said the patient - identified as Mrs A - had been “wrongly administered” the drug Amoxicillin when she was known to be allergic to penicillin.
While her death was not due to this, Ombudsman Jim Martin said there had been “unreasonable delay” in assessing and treating her condition as it worsened.
He stated: “It will be very distressing for Mrs A’s family to learn that the failings identified may have altered the outcome for Mrs A.”
His report said there had been “serious failings in care” and recommended NHS Lanarkshire apologise to the patient’s family.
The woman, who suffered from asthma, ischaemic heart disease and lung condition chronic obstructive pulmonary disease (COPD), was admitted to Monklands Hospital in Airdrie early in the morning of December 26 2014.
She died in the hospital just over a week later on January 2 2015.
Her husband, identified as Mr C, told ambulance staff who took her to hospital and medics working in the emergency department that she was allergic to penicillin, saying that on two previous occasions the drug had caused her to go into anaphylactic shock.
When the woman’s daughter, herself a nurse, visited the hospital on the evening of December 26, she saw in medical records her mother had been given Amoxicillin, a penicillin antibiotic.
The staff nurse who gave her the drug said she was “unsure” if Mrs A was wearing a red wristband, which would have identified her as suffering from allergies, at the time.
The Ombudsman’s report said while there was “human error”, the failure by staff to follow drug administration policies “was a serious incident and represented serious failings in care”.
Mr Martin said: “In this case, we have decided to issue a public report on Mr C’s complaint because the failings I found led to a significant personal injustice to Mr C and his family, and because we considered the board’s own investigation had not fully acknowledged the seriousness of what happened in Mrs A’s case, identified all the relevant learning and taken all necessary action to avoid a recurrence.”
The Ombudsman also highlighted a “failure by both nursing and medical staff to take appropriate action after Mrs A was wrongly administered Amoxicillin”.
His report stated: “It is of significant concern that there was an unreasonable delay in assessing and treating the deterioration in Mrs A’s condition.
“There were missed opportunities to consider a diagnosis of acute severe asthma in Mrs A, to adhere to national guidelines and to identify the severity of the deterioration in Mrs A’s condition earlier on in her admission.
“Mrs A should also have been referred earlier to the intensive care team. All of which represented a serious failure in Mrs A’s care.”
Irene Barkby, director of nursing at NHS Lanarkshire, said: “We aim to provide the highest standard of care at all times and therefore deeply regret any instance where we fail to meet this standard.
“It is clear from this report that the care and service we provided fell below the standards any patient should expect from NHS Lanarkshire.
“We fully accept the Ombudsman’s recommendations and we will once again be writing to apologise to the family for the failings identified in this case and for the distress caused.
“Since January 2015 a great deal of work has taken place to avoid similar incidents including introducing more robust measures to enhance medicine management.”