GP mythbuster 92: Anticoagulant monitoring in primary care

Anticoagulant medicines are used to treat and prevent blood clots. 

Many different medications can achieve anticoagulation. Here we will consider the management of patients taking oral anticoagulants.

• It is the responsibility of the prescriber to assure themselves that it is safe and appropriate to prescribe. 
• When prescribing and managing anticoagulants in secondary care, record this in line with practice procedure for recording hospital medicines. The record should be visible when a clinician is deciding on prescribing.

Managing patients taking warfarin

Details of Guidance on prescribing and managing warfarin are in the NICE oral anticoagulation clinical knowledge summary.

Patients who take warfarin need frequent monitoring. This is to ensure that the effect is within a safe range. Patients are usually issued with a 'yellow book'. This details their test results, their recommended dose and the date of their next test.

The practice should make sure all patients taking warfarin attend on time for measurement of their INR.

There are different models of care delivery for patients prescribed warfarin in primary care.

For example:

• The local anticoagulation service is usually based in a hospital haematology department.
  • The patient’s GP practice is still responsible for prescribing the warfarin.
  • The practice must make sure appropriate monitoring and dosing advice is in place to manage the patient safely.
  • This should be recorded in the patient record.
• The practice sends a blood sample to the laboratory for testing.
  • We expect the practice to manage the incoming test results. See GP mythbuster 46: Managing test results and clinical correspondence.
  • Include results in clinical decision making, managing the patient’s warfarin dose and deciding the monitoring interval.
• Near patient testing or point of care testing at the practice or a community pharmacy. Results are available immediately.
  • Clinicians can make clinical decisions about dosing and testing intervals. This may be a doctor, nurse or pharmacist with suitable training and experience.
  • They could also make them using a computerised decision support system. For example, INR star.
• The test is often carried out by a Health Care Assistant (HCA). The HCA must:
  • be appropriately trained to carry out INR testing and act in line with practice policy on managing anticoagulated patients. This may include the use of a computerised decision support tool. An appropriately trained prescriber should make any recommendations resulting in changes to a patient’s dosing regimen.

There should be a system of audit to review the consistency and accuracy of clinical decision-making.

Maintain equipment in line with manufacturer’s instructions. Keep records of internal and external quality assurance.

Prescribers may assess suitable patients to carry out their own blood tests. This depends on local commissioning arrangements.

Managing patients taking direct oral anticoagulants (DOACs)

There are 4 DOACs available in the UK. Each has its own specific indications and dosing information. NICE oral anticoagulation clinical knowledge summary provides detail on prescribing and managing patients.

Monitoring for patients on these newer medicines is less time consuming for both patients and practices.

Periodic review is necessary to check renal and liver functions which affect the way these medicines are metabolised. It is also necessary to assess compliance and check for adverse effects, such as bleeding. However, the anticoagulant effect is not monitored in the same way as warfarin.

It is important to prescribe the correct dose. This depends on factors, such as:

• age
• Weight
• renal function
• clinical indication.

The correct calculation must be used for renal function and recorded in the patient record.

What we look at

We use these regulations when we assess if a practice is safe, effective, caring, responsive and well-led. Anticoagulant monitoring relates to:

• Regulation 12 (Safe care and treatment)
• Regulation 17 (Good Governance)             
• Regulation 18 (Staffing) 

We will assess how providers ensure the following:

• People receive care, treatment and support that is evidence-based and in line with good practice standards.
• The provider’s systems ensure that staff are up-to-date with national legislation, evidence-based good practice and required standards.
• There are enough qualified, skilled, and experienced people, who receive appropriate and effective support, supervision, and development.
• There are clear responsibilities, roles, systems of accountability and good governance to manage and deliver good quality, sustainable care, treatment and support.
• Manage information about risk, performance and outcomes and share securely with others when appropriate.
• There are clear and effective governance, management and accountability arrangements. Staff understand their role and responsibilities. Managers can account for the actions, behaviours and performance of staff.