Skip to main content
Appointment slot issues within the NHS e-Referral Service (managing and minimising)

This guidance explains what NHS e-Referral Service appointment slot issues are, the best practice for managing them, and strategies for avoiding them in future.

What is an appointment slot issue

The NHS e-Referral Service (e-RS) combines electronic booking with a choice of place, date and time for first hospital or clinic appointments. Patients can choose their initial hospital or clinic appointment and book it in the GP surgery at the point of referral, or later at home on the phone or online.

When no clinic appointment is available for patients to book in e-RS, the referral can be forwarded (via the Manage Your Referral patient application) or deferred (via the professional application) to the patient’s chosen provider to enable the provider to book the patient an appointment. When a referral is forwarded or deferred, it will appear on that provider’s appointment slot issues (ASI) worklist.

There are two reasons why there may be no clinic appointments available on e-RS:

  1. In very rare circumstances, a technical issue can prevent an appointment slot from being shown or booked.
  2. The usual reason is that organisations providing directly bookable services have not made sufficient appointment slots available to e-RS.

Problems caused by not managing appointment slot issues effectively

While some appointment slot issues are inevitable, it is important that providers manage them in a timely and effective manner to minimise the effects on patients, referrers and their own staff. The impacts of poor ASI management include:

Patient confusion

When an ASI occurs, patients are informed that they will be contacted within a set number of days (based on clinical priority) by their chosen provider to have their appointment arranged. If this doesn’t happen, patients are directed to contact the service provider. The process of leaving the patient without any specific next steps can be confusing and cause unnecessary worry.

Clinical risks

Patients on an ASI worklist are not automatically visible on the trust’s Patient Tracking List (PTL). This increases the risk of them being missed or having an incorrect clock start recorded when their appointment is made.

Loss of audit trail - cancelling appointment requests

Providers sometimes believe that it is easier to manage an appointment slot issue by cancelling the appointment request from e-RS, printing the clinical information and managing the patient on a waiting list within their PAS . However, this deprives the patient of their ability to book to any alternative services that were on their shortlist as well as removing the audit trail for referrers – which can generate further queries and administration both for referring practices and providers.

Relationship with referral to treatment (RTT) clock starts for GP referrals

An RTT clock is started automatically when a patient successfully books their first outpatient appointment via e-RS. The clock start is triggered from the referral received field on the provider’s PAS which is automatically populated with the date on which the patient has made the booking. This is often also referred to as the date the patient converts their unique booking reference number (UBRN) or the date the provider receives notice of the referral.

When patients are unsuccessful in directly booking their first outpatient appointment via e-RS, the RTT clock should still be started from the date the patient attempted to book their appointment, which is also when the hospital receives the referral on their ASI worklist.

Relationship with RTT clock starts for referrals received through referral management, interface and clinical assessment services (intermediary services).

For RTT pathways that start within one of the services described above, the RTT clock start date is the date that the intermediary service received the original GP referral, not the date that the provider receives notice of the onward referral.

Further guidance relating to RTT and management of ASIs can be found in the NHS Improvement guidance document.

Best practice to manage and minimise appointment slot issue


Managing demand for a service is a shared responsibility between commissioners and providers. They need to work together to ensure that, where appropriate, a patient is treated at their first choice of provider.

  • under the NHS Constitution, commissioners must ensure that patients are able to exercise their legal right to choose which provider they go to for an outpatient appointment with a consultant or specialist
  • commissioners must put the necessary systems in place to ensure patients are offered and supported in their choice and allow patients to book appointments
  • commissioners should work with their local providers to ensure sufficient slots are always made available to allow patients to book their appointments


Referrers should offer the patient a shortlist that includes more than one service or provider in order to minimise the likelihood of the patient encountering an ASI. Referrers need to inform patients that:

  • when there are no appointment slots available there is a process within e-RS which enables their appointment request to be passed to their chosen provider who will then contact them to arrange an appointment
  • the same process allows them to forward their appointment request to their chosen provider if they try to book online and cannot see any available appointment slots
  • where ASIs do occur they can consider attending any other provider on their shortlist if they wish to do so
  • the referrer is able to print a letter from e-RS to give to the patient explaining what to do next and who to contact if they do not hear from the provider in the designated time

If a patient contacts their referrer because their chosen provider has not arranged an appointment, this should be escalated to their clinical commissioning group (CCG).

Using the defer to provider function

When a referrer attempts to book an appointment for a patient and there are no slots available, they can defer the responsibility for booking the appointment to the patient’s chosen provider using the defer to provider button.

NHS ERS appointment search screen

Note: if appointments are available to be booked but are not suitable or convenient for the patient, then the referral CANNOT be deferred to the provider. Instead, the referrer should discuss alternative providers with the patient.  Otherwise the patient will have to wait for suitable appointments to become available.

Once the referrer has selected the defer to provider option, the patient must choose which of the services with no slots they would like to be referred to – a referral request can only be deferred to one service. This is done by selecting one of the radio buttons on the deferral options details screen.

From the deferral options summary screen the referrer can confirm the patient’s choice of provider and print the appointment request letter. Both this screen and the letter will indicate a date by when the patient should have heard from their chosen provider, and will be based on the priority of the referral.

The date is calculated from the date of deferral plus:

  • two working days for two week wait referrals
  • five working days for urgent referrals
  • ten working days for routine referrals

The referrer can monitor the status of their patient’s referral via the awaiting booking/acceptance worklist, which will show the referral as deferred to provider until it is booked.

Patients will not be sent reminder to book letters while their referral is in a deferred to provider state. This helps to alleviate the frustration experienced by patients who have tried to book an appointment, been told that the provider will contact them and who then receive a letter reminding them to book their appointment.


Appointment slot issues compound waits by creating a backlog of patients whose waiting time has already started, creates a significant amount of avoidable administrative work and can cause patient safety issues as outlined above.

Providers must remember that:

  • they are contractually required to ensure that sufficient appointment slots for first outpatient appointments are available on e-RS as set out in the NHS Standard Contract 2018/19
  • all NHS organisations must have systems in place to promote equality and support all patients in the booking of their outpatient appointments
  • they are obliged to accept all clinically appropriate referrals and cannot turn patients away because they are not able to treat them within waiting time targets
  • the waiting time clock starts as soon as the referral appears on the provider’s ASI worklist within e-RS
  • if the referral is being sent initially through a clinical assessment service (CAS) then the waiting time starts from the date on which the original assessment appointment is booked
  • if the referral is sent initially through a referral assessment service (RAS) then the waiting time starts from the date that the clinical referral information is attached to the RAS referral and it then appears on the provider’s referrals for review worklist

Managing the Appointment Slot Issue worklist

Senior managers in provider organisations should ensure that all staff managing the ASI worklists are appropriately trained, are in the correct workgroups and have the necessary skills and authority to manage these referrals effectively and within the required timescales.

If a two week wait referral is entered into the ASI process, it will appear immediately at the top of the provider’s ASI worklist. As outlined above, the patient will expect to be contacted within two working days to arrange their appointment. Providers should make every endeavour to always ensure that there are sufficient appointments available for their two week wait services in order to minimise unnecessary stress to patients. Patients whose two week wait referrals appear on an ASI worklist should be contacted by the provider immediately to have an appointment booked. Urgent and routine patients expect to be contacted within one week and two weeks respectively.

The UBRN received date will turn red when the date given to the patient has already passed. Providers must not wait until the UBRN received date turns red on their worklist before they take action as it is likely that the patient will be in the process of contacting either their referrer or service provider to say that they have not received an appointment and potential patient safety issues may be occurring. It is recommended that all non two week wait patients are contacted within four working days to have their appointment arranged.

If the provider is unlikely to be able to arrange a patient’s appointment within the necessary timescales, the provider should contact the patient to explain the delay and provide details of how they can be contacted with any further queries. The provider should not direct the patient to contact their GP unless they now wish to book with a service not on their original shortlist.

Appointment slot issues worklist for providers

From the ASI worklist providers can perform the following actions:

  • add additional requirements
  • book appointment
  • cancel request
  • record ASI contact
  • review referral
  • view history
  • view request

The key actions are further explained below:

Book appointment

This will open the ‘Appointment Search Screen’, from where it is possible to book the appointment into:

  • an ordinary, available slot
  • a reserved slot (which is identified with an *)
  • a slot within the ‘slot protection’ time.

It is worth noting that where named clinician functionality has been used to search for services and an ASI has been experienced, this may be because there are no appointments available for the named clinician, but there may well be appointments still available within the service for generic referrals. Where a referrer has used a named clinician to search for services this will be displayed on the Deferral Options Summary screen and also on the Appointment Search screen.

Cancel request

Wherever possible the patient should have their appointment booked within e-RS. If this is not possible and the appointment has to be booked outside of e-RS, then the appointment request within e-RS must be cancelled and the reason ‘Patient booked outside the NHS e-Referral Service’ should be selected from the list. It is good practice to also enter the date and time of the new appointment in the accompanying free text box. This information will be available to all professional users who view the history of the referral.

Record ASI contact

This enables the provider to make a record of a contact (or attempted contact) with a patient whose referral is in the ASI process. The ‘Record ASI Contact’ option allows free text relating to the contact to be recorded and be available to others managing the process. ASI contacts are recorded in the history of the referral and are always available from any worklist that allows users to view the history. This functionality helps providers to manage their ASI worklists and maintain a record within e-RS of all attempts to contact a patient in order to book their appointment. Referrers and other users accessing the patient history will also be able to see both the number of attempted contacts and the recorded outcome of each.

Review referral

Provider clinicians can review the referral information and decide what the most appropriate course of action is for the patient prior to an appointment being booked.

There are three options when using this action:

  1. Refer/Book Now - Accepts the referral into the service and continues on to the service search screen where you can shortlist services for the patient to be booked in to.
  2. Accept and refer/book later - Accepts the referral into the service and puts the referral onto the Appointments for Booking worklist for admin staff to book an appointment for the patient.
  3. Return to referrer with advice - If the referral is not appropriate for the service or if further information is required from the referrer prior to acceptance, the referral can be sent back to the referring clinician with comments from the provider clinician.

View request

This enables the provider clinician to review the clinical referral information prior to the booking to ensure the patient’s referral does not remain on the worklist if it is clinically inappropriate for them to wait.

Note: referrals will be removed from the worklist after 180 days if no action is taken.

Strategies for reducing appointment slot issues

The NHS e-Referral Service programme team has had conversations with a number of providers that consistently keep their level of appointment slot issues low. There are number of key lessons that can be learned from the processes that these providers have in place:

Ensure that e-RS capacity management is embedded in existing capacity management review processes, supported by strong escalation processes.

Royal Devon and Exeter NHS Foundation Trust: “We send an ASI report to all specialties 3 times a week, and ASIs are discussed in fortnightly Access meetings”

Bolton NHS Foundation Trust: “Weekly meeting is chaired by Divisional Director of Operations, with specialty Business Managers in attendance. Figures are supplied each week showing e-RS polling ranges and capacity and demand figures”

Cambridge University Hospitals NHS Foundation Trust: “We produce and circulate a daily report to the service delivery managers which highlights how many ASIs were received for that day and any overdue ASIs not currently booked. Services continually receiving a high volume of ASIs will be contacted by the Outpatient Service team to discuss the on-going issues and produce a management plan to provide additional capacity.

Bolton NHS Foundation Trust: “issues are passed to the relevant business manager, who will contact the doctors to discuss capacity issues and how to resolve”

Liverpool Women’s NHS Foundation Trust: “escalation to divisional business support managers who will raise with service manager”

Ensure that slot poll ranges align with or exceed waits for patients referred by other means

Keeping slot poll ranges shorter than the actual waiting time for a service only results in patients being unable to book their appointment directly.

There are no RTT benefits to providers in keeping polling ranges artificially low, as the patient’s waiting time starts at the point that they appear on the appointment slot issues worklist (or earlier, if they have been through a primary care interface service or referral management centre).

Allowing the patient to book directly also has additional benefits; the provider has immediate access to referral information, the patient is automatically registered on the provider’s patient administration system (PAS) and the patient will also feature on the provider’s patient tracking list (PTL), highlighting RTT pressures and minimising the size of the appointment slot issues worklist, which can sometimes act as a hidden waiting list (as the patients are not on the PTL).

Keeping polling ranges long enough to enable patients to book while supporting organisations in their delivery of RTT requires good management of capacity and demand. Models for analysing outpatient capacity and demand have been made available by NHS Improvement.

Longer polling ranges can present challenges, particularly around the issue of consultant leave notification. The quotations below demonstrate how some providers manage this challenge:

Nottingham University Hospitals NHS Trust: “Most of our polling ranges go over six weeks. This does present a challenge in terms of the consultant leave policy. Most leave is booked well in advance by consultants but if leave is requested within the policy then if we cannot get another clinician to see the patients, then [patients] will be moved to the next available slot. Not an ideal solution but we are balancing two demands here”

Bolton NHS Foundation Trust: “The 6 week leave rule does on occasions cause us problems. We would use our firebreak clinics first, once used up we would ask for extra clinics. As a last resort we would do rolling moves.”

Royal Devon and Exeter NHS Foundation Trust: “Our wish is to move back to polling ranges of 6 weeks, but this is a gradual process as we resolve our capacity issues. We use our Registrars, SHOs etc. to cover consultant cancellations – where we can’t we will tend to shift all patients’ appointments back. However, this is rare”.

Allocate all new slots to the NHS e-Referral Service

If you regularly hold back slots in order to meet your ASI demands, you are effectively compiling tomorrow’s ASI list. As far as possible, align your booking processes and timings for paper etc. referrals with e-RS to prevent the notion of e-RS patients queue jumping.

Audit appropriateness of referrals and regularly feedback to referrers and consultants

If you regularly receive inappropriate referrals into a service then review your directory of services (DOS) entry in consultation with referrers to find out why and minimise reoccurrences.

You may also want to consider using the review referral action to assess the appropriateness of referrals before the patient has an appointment booked. This can allow services with complex care pathways to reduce the number of slots that are taken up by inappropriate referrals.

Enable referrers to request advice and guidance through e-RS

Detailed guidance and case studies are available from NHS Digital. However, there are examples of advice and guidance significantly reducing demand for outpatient appointments.

Consider creating additional capacity by offering non consultant led services on e-RS

Where there are genuine demand and capacity issues in particular services, providers and commissioners should work together to look at making alternative options available, potentially through more community type services.

Appointment slot issues management information

The correct use of data and information contained within the e-RS is fundamental to the management of ASIs by both commissioners and providers. It enables the incidence of ASIs to be calculated, monitored and discussed at national, regional and local levels.

The monthly ASI report enables providers and commissioners to look at ASIs by type and by specialty. Importantly, it helps to compare the number of ASIs with the number of overall bookings, showing this as a ratio. All providers should review this report regularly to understand their current ASI position and track their progress over time. These reports are available within the reports and statistics section of the NHS Digital website.

There are two slot availability enquiries in e-RS which provide real-time information on used and unused slots by specialty, clinic type and priority over a specified time period. One is available to those with a service definer role within provider organisations and the other to those with a commissioner role, showing information for a specified provider.

For providers there are two reports on e-RS, which are available to those with an information analyst role. These show past slot utilisation (S6) and future slot utilisation (S7) at specialty and service level. In the future slot utilisation report, available slots, appointments booked via e-RS, and unused slots are displayed by priority and week, over a 26-week period. In the past slot utilisation report, available slots, appointments booked via e-RS, and unused slots are displayed by priority and week for the last thirteen weeks.

Finally, users with the information analyst role who work for commissioners or providers are able to see detailed information on the management of all referrals, including ASIs, within the e-RS extracts. However, users will require high level analysis skills and experience of using the NHS e-Referral Service to interpret the data contained within the extracts.

Future ASI improvements and support information

Future improvements and supporting information on the ASI process can be found within the NHS e-Referral Service system Help (HSCN connection required).

Last edited: 21 April 2021 8:41 am