AN Urgent Care Centre criticised by the health watchdog is "safe and effective" for the majority of its patients, GPs have said.
But Croydon Clinical Commissioning Group (CCG), which contracts a private company to operate the service, said concerns that a "small number" deteriorate and need to be transferred to A&E are being taken "very seriously".
The Care Quality Commission (CQC) has raised "serious concerns" about the unit, which is attached to the emergency department at Croydon University Hospital but run by Virgin Care.
Its staff are supposed to assess patients within 20 minutes of arriving at the hospital.
But, during an inspection of the trust as a whole in September, the CQC learned of two patients whose conditions may have worsened because they were made to wait longer.
The CQC report, published last Thursday, concluded care provided by the Urgent Care Centre was "not safe".
Croydon CCG, Virgin Care and Croydon Health Services (CHS), the trust which runs the hospital, have met to agree improvements.
Paula Swann, chief officer of Croydon CCG, said: "The Urgent Care Centre is set up to take inpatients with minor illnesses and injuries, and the service is safe and effective for those patients.
"However, the issues raised by the CQC concern the small number of patients admitted to the centre who deteriorate or, for some other reason, need to subsequently transfer to the emergency department.
"This is an important issue and one we are taking very seriously as the safety of every patient is important to us.
"We have been working with the provider of the Urgent Care Centre and CHS to address these issues, which we have been aware of since concerns from the September inspection were raised."
Ms Swann said a new system was now in place to deal with the issues. An unannounced visit to the centre has already taken place, and more are scheduled.
Adults who walk into the London Road hospital's A&E department report to reception, which is run by Virgin Care Staff.
People with certain conditions (chest pain, for example) should be sent straight through to A&E.
Others must be assessed by a Virgin Care professional within 20 minutes.
During the CQC's two-day inspection of the hospital in September, its team noted two cases where the conditions of two patients worsened potentially as a result of waiting more than 20 minutes.
"We were so concerned about the potential impact of this on patient safety that we ordered an urgent inspection of the Urgent Care Centre," the CQC report said.
"Although Croydon University Hospital staff are trying hard to work in collaboration with the other provider, the provision of care was not safe."
Ms Swann said: "We will continue to monitor the situation very closely to ensure both the Urgent Care Centre provider and CHS deliver the improvements that are necessary."
A previous CQC inspection, in July, said people were not being given appropriate information in relation to their care and treatment.
The results of the latest inspection are expected to be published in December.
The spokesperson Virgin Care said: "We are not aware of any evidence the system Croydon CCG had specified led to bad outcomes for any patients, however following discussion with CQC, Croydon CCG has decided to pilot a slight change to the process and we will continue to provide care in line with the CCG's specification."
