There is no minimum standard of training for healthcare assistants before they can work unsupervised, an independent report has found.
Workers should get at least two weeks' training to prepare them for providing basic care in hospitals, care homes and at home in England, its author said.
Journalist Camilla Cavendish also said some staff were only given a training DVD to watch before starting work.
The review was set up in the wake of the Stafford Hospital scandal.
Ms Cavendish found that HCAs - who provide basic care such as feeding and washing patients - were given no "compulsory or consistent" training, and said some were doing tasks usually performed by doctors or nurses, such as taking blood.
Speaking to BBC Radio 4's Today programme, Ms Cavendish said HCAs should have to earn a "Certificate of Fundamental Care".
The qualification would link HCA training to nurse training, making it easier for staff to progress up the career ladder, should they wish to.
All new recruits would need to obtain the certificate and existing HCAs would need to prove they had the equivalent training.
Ms Cavendish said details of the training had not been agreed, but it would include basics such as first aid, infection control and dementia awareness, and would take a "couple of weeks".
"Ongoing supervision" by employers would be essential after that, she said.
Currently, there is no consistent qualification or training for HCAs, with employers deciding for themselves what training is needed.
The government will provide a formal response to the review, along with its response to the Francis Report into the Mid Staffordshire public inquiry, in the autumn.
It has already promised to establish "minimum training standards" for HCAs by spring 2014.
But Health Secretary Jeremy Hunt refused to initiate full-blown regulation, saying it could lead to a "bureaucratic quagmire".
A public inquiry into Stafford Hospital found hundreds of patients had died following neglect and abuse between 2005 and 2008.
'Most caring of all'
There are more than 1.3 million frontline staff who are not registered nurses, according to the Cavendish Review.
They provide some of the most personal and fundamental care such as turning people in bed so they do not get pressure sores and helping people to eat and wash.
The review says the quality of training and support that care workers receive in the NHS and social care system varies between organisations and, in some cases, is lacking.
As well as suggesting the new training certificate, it suggests calling HCAs Nursing Assistants in recognition of the important work they do.
Ms Cavendish said: "Patient safety in the NHS and social care depends on recognising the contribution of support workers, valuing and training them as part of a team.
"For people to get the best care, there must be less complexity and duplication and a greater focus on ensuring that support staff are treated with the seriousness they deserve - for some of them are the most caring of all."
HCA Trudie Brailey told the BBC staff are put in a "very difficult position" when they are asked to carry out procedures they are not qualified to do.
She said there is sometimes no registered nurse free to do a job, so "you do the best that you can, and it makes you judge yourself".
Peter Carter, of the Royal College of Nursing, was concerned that without mandatory regulation there would be a danger that any staff who were found to be unsuitable could move from one employer to another unchecked.
"The priority must now be to underpin the recommendations made by Camilla Cavendish in the regulatory structure which governs care," he said.
Christina McAnea, of Unison, said that in some hospitals HCA's were treated as "cheap labour".
"Common training standards across health and social care are long overdue and welcome," she added.