Patients benefit from anticoagulation monitoring in primary care but optimum management depends on the right decision-making support, says Dr Alan Begg

Oral anticoagulation therapy, usually warfarin, has increasingly been used to treat a range of vascular conditions. Anticoagulants, given long term, have significant benefits in the prevention of serious vascular events in high-risk patients and in the treatment of acute arterial or venous thrombosis (Table 1, below).

Table 1: Indications for oral anticoagulation1
Target INR Indication

2 - 2.5

Prophylaxis of deep vein thrombosis (DVT) including surgery in high-risk patients

2.5 Treatment of DVT and pulmonary embolism (or recurrence off warfarin), atrial fibrillation, cardioversion, dilated cardiomyopathy, mural thrombus post-myocardial infarction and rheumatic mitral valve disease
3.5 Recurrent DVT and pulmonary embolism (in patients on warfarin and INR >2) and mechanical prosthetic heart valves

However, full-dose anticoagulation can lead to major intracranial, gastrointestinal or retroperitoneal haemorrhage, and the anticoagulant effect should therefore be closely monitored.

The international normalised ratio (INR) measures the delay in the clotting of blood caused by the anticoagulant,1 and quality assurance procedures can minimise any potential variation in results.

Under the nGMS contract, practices can now provide anticoagulation monitoring as a national enhanced service, and be financially rewarded for doing so.

A national enhanced service

Anticoagulation services have not always been hospital based,2,3 and the recent shift back to primary care with increasing numbers of patients has been generally welcomed.4 A surgery-based, pharmacist-led anticoagulation clinic can achieve good therapeutic control,5 and nurse-led anticoagulation clinics provide care that is at least as good as routine hospital follow-up.6

A national enhanced service for anticoagulation monitoring should:

  • Provide therapy (normally initiated in secondary care) for recognised indications for a specified length of time;
  • Ensure proper anticoagulation control;
  • Be convenient for the patient;
  • Carry out regular review of the need to continue therapy.

The essential components of the service are outlined in Table 2 (below).

Table 2: Components of an anticoagulation service

Patient register

This should be up to date and include name, date of birth, indication, length of treatment and target INR

Read code .66Q

Patient recall A system should be in place to ensure systematic call and recall of patients
Multidisciplinary working Professionals with the appropriate skills should work closely together
Education for patients and carers Patients and carers should have a full awareness of the condition and potential complications. Patients should be issued with a national treatment booklet (supplier’s address is given in the British National Formulary)
Patient management plan An individually tailored plan should be issued, giving diagnosis, duration of therapy and therapeutic range
Full clinical review This should be carried out at least annually. It should include a check for potential complications and ensure that all information is recorded
Clinical records These should be adequate and up to date
Audit The level of care should be audited against the agreed criteria
Training All staff involved should have the necessary skills, proven competencies and also receive regular updates
Review All practices should perform an annual review, to include: number of patients being monitored, indications for anticoagulation and duration of treatment, and details of any computer-assisted decision-making equipment (and arrangements for quality assurance), near-patient testing equipment (and arrangements for quality assurance), training and education and standards used for the control of anticoagulation

Practice-based monitoring of anticoagulation

For the past 15 years, our practice, like others, has used a simple system that is convenient for patients yet enables INR to be tested at an approved site, avoiding the problems of near-patient testing.3

We have provided a fully audited enhanced service with the medical experience, training and competence to satisfy appraisal, and this is now being recognised under the nGMS contract.

Doubts have been raised about the quality of data collection at practice level and the under-reporting of adverse events; one study of oral anticoagulation centres found that half had reported no adverse events.7 However, it is a condition of participation in this national enhanced service that the clinical governance lead for the primary care organisation should be notified, within 72 hours, of any emergency admission or death related to anticoagulation.

Clinical information system

The strength of our practice’s approach is a web-based clinical information system designed specifically for monitoring patients taking warfarin.8 The system, Central Vision Monitor AC, forms a module of an electronic health record 9 and will eventually operate across our entire region. It provides all authorised clinicians, whether in primary or secondary care, with access to all the required information and components of an anticoagulation service, including laboratory results, point of care results and dosing support (Figure 1, below).

Figure 1: Screen view of web-based clinical information system for anticoagulant monitoring

Computerised decision support improves anticoagulant management of patients in a hospital setting,10 and provides better control in a general practice based anticoagulation clinic.11

Point of care testing

Point of care testing (POCT) refers to any analytical test performed for a patient outside the conventional laboratory setting. Other terms used include ‘near-patient testing’ and ‘bedside testing’, although POCT now tends to be the one most commonly used.

There is confusion within the nGMS contract documentation, as the term near-patient testing is used to refer to disease-modifying drug monitoring, where the blood tests are invariably carried out in the laboratory. A systematic review of the evaluation of near-patient testing in primary care revealed a need for high quality evaluation of the tests’ performance and effectiveness before they are used more widely.12

There is no research into whether POCT affects patient outcomes; however, POCT of INR measurement in the community can compare well with hospital laboratory measurement.13

The advantages and disadvantages of POCT are outlined in Box 1 (below), and Box 2 (below) gives useful tips on using the method.14

Box 1: Point of care testing
  • The location is convenient for the patient
  • It is ideal for remote and rural practices a long distance from the hospital laboratory
  • There is less need to transport blood samples
  • The result is available immediately for:
    • dose adjustment
    • out of control action
  • There is the potential for patient self-management
  • It is significantly more expensive
  • It is more time consuming
  • There is a need for initial and ongoing staff training
  • There is an increased risk of bio-hazards
  • Equipment is duplicated
  • There is a need to calibrate the testing device and audit results
  • Infrequent use of the testing device can lead to inaccuracy
  • The testing device requires ongoing maintenance
  • Full drug and medical records may not be available at the clinic location
  • For housebound patients it may be more efficient to send the sample to a laboratory
  • The requirement for laboratory testing remains


Box 2: Top 10 tips for point of care testing14
  1. Involve your local hospital laboratory
  2. Appoint a coordinator when establishing the service
  3. Ensure that all health and safety issues are addressed
  4. Only trained staff whose competence has been established should be involved
  5. Be aware of when the device should not be used
  6. Establish standard operating procedures including the manufacturer’s instructions for use
  7. Audit the quality control system
  8. Results should be reviewed by qualified staff with reference to patient’s history
  9. Full record keeping is essential
  10. Maintain devices in accordance with the manufacturer’s guidance

As there is no obligation for practices to provide an enhanced service, our local health board is moving to an area-wide scheme similar to the Birmingham model.6This will continue to use the successful Monitor AC system but will be based primarily on POCT, despite its limitations and the increased demand it places on resources (Figure 2, below).

Figure 2: Comparison of the processes of laboratory testing and point of care testing


We currently have 55 patients undergoing anticoagulant monitoring, equating to 83 per 10 000 patients.

Level 3 remuneration (laboratory testing) is £103.29 per patient, giving a weekly practice income of £109.24. In the second half of last year we carried out 17 tests each week (at £6.42 per test), 30% of which were carried out in the patient’s home. Level 4 remuneration (point of care testing) is £113.55 per patient. Both rates will be increased by 3.225% in 2005/06.

The Quality Management and Analysis System (QMAS),15 the national system for measuring quality of care which is already installed on the practice IT system, does not at present provide or extract information on enhanced services. Claim information is extracted from the reporting database of the practice clinical system and submitted quarterly for payment.

Further developments

Patient self-management

Just as diabetes patients are now encouraged to monitor their own glucose levels, home INR monitoring may become the norm for patients taking oral anticoagulants, reducing the need for professionally led clinics.

Self-management can mean closer adherence and increased control of treatment with oral anticoagulants.16 Three-quarters of unselected patients are able to complete training for self-monitoring successfully,17 and this can be as safe as primary care management 18 and as good as laboratory testing.19


For anticoagulation therapy to be effective, national guidelines, widely disseminated and implemented, are needed.20 When deciding how best to develop and provide an enhanced service for anticoagulant monitoring, practices should consider how to maximise benefits and convenience to patients. The service should be evidence-based and the financial rewards need to be balanced against the demands on practice staff time.


I would like to thank the Townhead practice team for their help in preparing this article.


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Guidelines in Practice, February 2005, Volume 8(2)
© 2005 MGP Ltd
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