Plans for a single patient record for the NHS in England will be debated for the first time by MPs on Monday.
The aim is to combine GP, hospital and social care data so patients don't have to keep repeating their medical history unnecessarily at appointments.
A&E clinicians, who often cannot access GP patient records, will be able to quickly check patients' complete histories, medication and allergies if they arrive needing urgent care.
However, concerns have been raised, by the British Medical Association among others, about the sensitivity of patient data and who will have access to it under the new system.
Health and Social Care Secretary James Murray has said it will be "crucial to have strict legal safeguards in place".
Murray, who replaced Wes Streeting in May, said it can be "distressing" for some patients to have to repeat their medical history to different professionals.
Speaking to BBC Breakfast, he said: "We will make sure only specified people can access the data and there will be an audit trail of exactly who has accessed the data.
"There will be strong cyber security protections for it as well.
"We will protect this data like we do all of our health data today."
The Department of Health and Social Care has published projections suggesting that 20,000 fewer patients a year will have to go to A&E thanks to the single patient record and other reforms to NHS treatment.
This is because it is assumed there will be fewer patients wrongly diagnosed because of lack of access to records and more of the frail elderly will be treated in their communities.
Paramedics will be able to see full information on a patient they are blue-lighting to hospital.
The single patient record will be made available on the NHS App and the new system would be rolled out from 2027.
In some parts of England, there is already limited shared data access but the new plan is designed to ensure consistency across the whole system.
One surgeon revealed recently that he had to cancel a kidney transplant because he could not check the patient's history quickly enough. He said there were symptoms which had to be analysed in more detail but there was no access to GP records over a weekend.
Pregnant women have to go through their entire medical history from memory at their first midwife appointment, because midwives don't have access to official records.
Carers, according to officials, will benefit from the planned new system because they will be able to find out up-to-date information on a patient's treatment and medication.
Officials say GPs will save time because they will be able to find information about their patients more quickly.
Dr Deb Gompertz of the British Geriatric Society said: "Older people are among the highest users of NHS services, often receiving care from multiple teams across hospitals, community services and primary care. Better sharing of information has the potential to improve continuity of care."
But concerns have been raised by the British Medical Association (BMA) about the security of pooled data.
Dr David Wrigley, deputy chair of the BMA's GP committee England, said he had "real concerns" about what the plans would mean for confidentiality.
He said: "GPs have protected patients' confidential records since the inception of the NHS in 1948, a legal duty that they take incredibly seriously. However, we need clarity that this important GP oversight will not be taken away, otherwise it will raise serious questions about who is safeguarding patients' data."
Helga Pile, head of health at public services union Unison, told BBC Radio 4's Today programme the concept of a single patient record is "something that all staff working in the NHS can see the benefit of".
"But it's really important that it's done in the right way so that matters about who is involved and how it is done," she added.
"Patients and staff are really concerned about the sensitivity of patient data - who can see it - but they also are really acutely aware about how lucrative it is for companies to get hold of that data and to make money out of it."
The single patient record is part of the NHS Modernisation Bill which has its second reading in the House of Commons on Monday.
The bill also includes the abolition of NHS England and the scrapping of Healthwatch, the independent patient representative organisation. Ministers say the aim is to "reduce layers of bureaucracy" and free up resources for frontline services.
