Support staff play a key role in the classroom
Schools are putting teaching assistants under increasing pressure to carry out medical procedures without appropriate training, a union warns.
Unison says most support staff only hold a basic first aid certificate.
But some are being asked to carry out procedures such as administering drugs for heart problems, changing colostomy bags and testing blood sugar levels.
Government guidelines say staff must be properly trained before carrying out any medical procedure.
And they stress that it is the responsibility of schools to make sure that is happening.
Unison is calling for the introduction of new, tougher guidelines setting out what support staff should and should not be asked to do.
The survey found 85% of the 334 respondents were expected to provide medical support, and 70% to administer medicines as part of their job - even though these are voluntary duties.
Lack of competence
One in four respondents did not feel competent and comfortable with the responsibility of administering medicines or providing medical support.
And one in three said they were not familiar with school policy on how to do it.
Michelle McKenna, a schools support worker from Durham, said: "I know school support staff who routinely have to change colostomy bags, administer drugs or epilepsy medicine.
"Some staff have to do tube feeding or take children as old as their early teens into the toilet - often without proper training.
"Support staff are really worried that they will make a mistake.
"But they are even more worried about the safety of the children they look after.
"Many of the procedures they are being asked to do are above and beyond what they signed up to do, and it is only a matter of time before something terrible happens."
Christina McAnea, our Unison's National Secretary of Education and Children's Services, said the survey had revealed a chronic lack of training and support for school staff, who were expected to provide a wide range of medical support to pupils.
She said: "Many reported feeling "emotionally blackmailed" into doing these tasks and were worried about the potential risks to children.
"Imagine the pressure of being told that a child could not go on a trip unless you would change their colostomy bag, but you hadn't had specialist training to do that job?"
Ms McAnea said safety should be a top priority for children who had medical needs at school.
This could only happen where lines of responsibility were clear, and staff were properly trained.
"The current situation cannot continue. We are bound to see a serious incident if schools don't get the help they need to manage children's special medical needs.
"The current arrangements are an accident waiting to happen."
The Department for Children, Schools and Families said there was no legal duty on school staff to manage a pupil's medicine or support a child's medical need.
But it was expected that schools make every effort to ensure that children with medical needs are able to attend school regularly and take part in school activities, wherever reasonable.
A spokesperson said: "It is vital that all members of school staff are properly trained to carry out the tasks expected of them. As the employer, local authorities should make sure this happens.
"Schools have a duty to protect the health and safety of their pupils, and this may involve putting reasonable arrangements in place for children with medical needs."
Saranjit Sihota, of the charity Diabetes UK, said: "Given that school attendance isn't voluntary, it is wholly unacceptable that the provision of essential support at school is a voluntary matter.
"We want the government to place a statutory duty on school governing bodies to ensure all children and young people receive the support they need to manage their health condition and lead a full school life."