Referral of Patients to Anticoagulant Clinic

N.B. If a patient has been on warfarin pre-admission, see guideline on Appropriate and Safe Conversion from Warfarin to a DOAC.


Patients being discharged from hospital on vitamin K antagonists (warfarin or acenocoumarol) will usually be in an unstable phase of anticoagulation. It is therefore essential that the transition of anticoagulant monitoring from hospital care to the community or outpatient clinic is well organised and clearly documented for the patient and clinical staff involved.

Anticoagulant service providers

All NHSGGC adult patients taking, or to be commenced on, a vitamin K antagonist (VKA) must be referred to Glasgow and Clyde Anticoagulation Service (GCAS, see Appendix 6 for contact details) before discharge from hospital for their ongoing dosing and monitoring. GPs should not be asked to undertake routine INR monitoring. A referral should be made for all vitamin K antagonist-treated patients regardless of whether their anticoagulation is considered stable or not.

For patients resident outwith NHSGGC, please contact the patient's GP to identify the most appropriate anticoagulant provider for their Health Board. Information may also be available from GCAS (see Appendix 6 contact details).

Referral to GCAS

Referrals should be made electronically via TrakCare for all VKA patients, whether they are started on treatment prior to or during hospital admission, or if they are still to commence on it as an outpatient.

  • Ensure that the request form contains as much information as possible to facilitate ongoing dosing and monitoring which includes:
    • Indication for warfarin / acenocoumarol, target INR and intended duration of treatment
    • Details of the last 3-5 most recent INRs, warfarin doses and dates (if available)
    • Details of anything that may affect anticoagulant control e.g. interacting medications
    • If the patient is on low molecular weight heparin bridging therapy
    • If the patient is on antiplatelet medication, which one and if this has to continue with VKA or not.
    • Referring consultant, ward and contact details. Failure to provide these details may result in delay in executing the referral within the 1 hour window.

GCAS aim to process referrals within 1 hour of referral during the working week (Mon–Fri 9am-4pm). Weekend / out-of-hours referrals will be processed on the next working day. GCAS staff will phone the ward with an appointment for the patient, but if the patient has already been discharged then GCAS staff will require telephone contact details for the patient in order to appoint them.

Prior to discharge

Key recommendations are as follows:

  • Appointment – ensure referral is made via TrakCare to ensure prompt follow up is arranged for all patients discharged on a VKA (this will usually be scheduled for 3-7 days following discharge).
  • Home visits / transport - if the patient is housebound or is unable to attend a clinic appointment due to lack of transport (or friends / relatives providing transport), a home visit can be arranged. Contact GCAS office (see Appendix 6 for contact details) for NHSGGC patients or their GP if resident outwith NHSGGC.
  • Issue patient with a yellow anticoagulant booklet. Ensure the booklet includes:
    • Patient's details
    • 3-5 most recent INR results (where available) and associated VKA doses (including dose at discharge) to allow safe dosing at their first post-discharge anticoagulant clinic visit
    • Details of the next anticoagulant appointment if available at time of discharge, otherwise GCAS staff will contact the ward and patient directly. Therefore ensure patient contact details are provided on the referral form.
  • Patient education – ensure patient understands indication, interacting factors, bleeding risks and doses of VKA to be taken until first anticoagulant appointment.
  • Ensure patients are discharged with a sufficient supply of VKA. 

Patients already on Vitamin K antagonist prior to this admission

  • These patients can often be discharged in a less stable anticoagulant state and sometimes on a different dose. They may be on new medicines which could interact with VKA.
  • They will already have an existing anticoagulant clinic appointment but you must make a new referral to GCAS using the TrakCare form to obtain an updated appointment and ensure that their appointment is within 3-7 days of discharge.
  • Update the yellow booklet with appointment details and include 3-5 of the most recent INR results and corresponding VKA doses from their inpatient stay.

Patients to be commenced on warfarin as an outpatient

  • Patients requiring elective initiation of warfarin (e.g. asymptomatic atrial fibrillation) can be referred to their local hospital anticoagulant clinic for this to be commenced as an outpatient. Use the electronic referral form on TrakCare (see details above) to make the referral.
  • On the referral form where it says 'when was the anticoagulation started', click on the spy glass and select option 'to be commenced at the anticoagulation clinic'. Include the same referral information as for inpatient referrals (see above).
  • It is recommended that such patients do not start anticoagulant therapy in advance of their first anticoagulant clinic appointment. GCAS will contact the patient directly with their anticoagulant clinic appointment and endeavour to appoint these patients within 2 weeks of referral.


Guideline reviewed: July 2023

Page last updated: December 2023