A coroner has raised concerns over "confusion and errors" caused by "generically labelled" drips following the death of a woman.
Susan Warby, 57, died at West Suffolk Hospital in 2018, and coroner Nigel Parsley found her death was contributed to by administering the wrong drip.
Her death had prompted a whistleblower to highlight errors in her care.
Mr Parsley has now written to Health Secretary Matt Hancock over intravenous drip labels and staff training.
Mrs Warby, from Bury St Edmunds, was admitted to hospital after collapsing at home with a perforated bowel on 26 July and died in the intensive care unit on 30 August from multi-organ failure and other complications.
Delivering a narrative conclusion at the inquest in September, Mr Parsley said: "Susan Warby died as the result of the progression of a naturally occurring illness, contributed to by unnecessary insulin treatment, caused by erroneous blood test results."
In a prevention of future deaths report, Mr Parsley said from the evidence "it was clear that packaging and visual identification aids available for intravenous fluids... were not sufficiently distinctive".
He added: "The number of cases identified where the incorrect fluid is being used... clearly demonstrates the confusion and errors which occur when using generically labelled intravenous fluids with an arterial line transfusion set."
He said in Mrs Warby's case "the error of the incorrect intravenous fluid... was exacerbated by medical staff using an incorrect technique when drawing her blood samples".
The coroner said the hospital had since put in place new training and operational regimes for staff.
'Knocked sideways' by letter
But in his report, written to Mr Hancock and the Medicines and Healthcare products Regulatory Agency, the coroner asked for a wider review "given the apparent prevalence of errors regarding the incorrect use of intravenous fluids and incorrect blood sampling techniques involving arterial lines".
Earlier this year, her widower Jon Warby said he was "knocked sideways" when an anonymous letter highlighted errors in his wife's care.
Following reports the hospital had asked doctors for fingerprints and handwriting samples to identify the whistleblower, the Doctors' Association described the attempt as a "witch hunt".
A West Suffolk NHS Foundation Trust spokesman said: "We offer Mrs Warby's family our deepest sympathies. Aspects of her care could and should have been better and for this we apologise."
He added they have put in "enhanced procedures and safeguards to improve the quality of the care we provide".
A MHRA spokeswoman said the authority was "aware" of Mr Parsley's report and were "currently analysing the report and preparing a response to the coroner".
A spokeswoman for Mr Hancock's Department of Health and Social Care, said it would also respond to the coroner in due course.
The Suffolk Coroner's office said the deadline for a response to his report from those two bodies had been extended from 20 November to 15 January, due to the coronavirus pandemic.