Receptionists with no clinical training are making decisions about patient care at doctors' surgeries in Croydon, according to a report.
Many patients do not know who their GP and are not “actively involved” in choices about their treatment, Healthwatch Croydon found.
The watchdog surveyed 1,856 patients across the borough's 59 practices between September 2015 and August this year.
It noted receptionists were taking an “enhanced role” in arranging repeat prescriptions and informing patients of test results.
The report, published on Tuesday, said: "This raises questions over safeguards and training. Some patients experience delays, and observe ‘confusion’ between the practice and hospital."
One patient, who was not named, told Healthwatch: "One time I asked about some results, I was told one thing and then another.
"I was told I was fine, as the receptionist read the report, but I know that my cholesterol would not have suddenly gone back to normal, so I queried this, and they said they had not read it properly."
The report found most patients were satisfied with their care but some “feel they are not actively involved in decision-making” and that doctors could be “too quick” to prescribe medication without considering alternative forms of treatment.
Booking appointments could be "problematic", particularly by phone, with patients at one practice commonly on hold for an hour.
The report said: "This not only illustrates inconvenience, but the acute demands on the system."
Healthwatch recommended GP surgeries fully train reception staff to make clinical judgements, listen to patients' concerns before making decisions about treatment and offer patients greater flexibility when booking appointments.
Charlie Ladyman, chief executive of Healthwatch Croydon, said: “It is good that Croydon residents broadly believe GP services are of high quality, and that there is an appreciation that services are under pressure.
“However issues of capacity, assurance and listening to patients need to be addressed.
“These issues are core to the success of any health service and with GPs being the most used service, it is all the more important.”
Dr Agnelo Fernandes, a GP and assistant clinical chair of Croydon Clinical Commissioning Group which comprises of the borough's practices, admitted the report showed care was "variable".
He added: “We look forward to working with Healthwatch to understand these issues more closely.
“We are collaborating with our practices and with NHS England to further develop and improve GP services in line with patients’ feedback and with the NHS five-year forward view.”
Healthwatch Croydon’s annual general meeting on October 5 will focus on how GP services in the borough will change over the next five years.
It will be held at the community space in Bernard Weatherill House between 11.30am and 2.30pm.