What's New

DVT Issues

There are a few simple, minor modifications to the pathway that GPs could make which would really help both patients and the Ultrasound dept match capacity and demand.

The delay between clinical assessment and the scan, although an irritation, does allow a negative d-dimer to test to weed out unnecessary scans and free up valuable capacity, and ‘holding anticoagulation’ can keep patients safe.

  1. When referring via ICE a patient with possible DVT (Wells Score ≥ 2), please take a d-dimer and U+Es blood at the time of assessment. (If negative, the d-dimer is a good rule out test and the scan can safely be avoided).
  2. Give the patient a prescription for a few days of NOAC e.g. Rivaroxaban 15mg twice daily – six tablets is usually adequate - until diagnosis confirmed or refuted. (Rivaroxaban and all similar NOACs are really expensive and should be used parsimoniously!).
  3. If the first scan is negative, a second ultrasound is required ONLY IF the d-dimer is positive.
  4. If DVT is confirmed, patients will require three or more months of anticoagulation (Rivaroxaban 15mg twice daily, always with food for three weeks then 20mg once daily is usual regime – IF renal function adequate – see BNF – hence the importance of the U+E result).

Contact: Charles.buckley@nhs.net for any more information.

GPs are therefore encouraged under the 2014 Locally Enhanced Service scheme to manage newly presenting DVTs in primary care according to the following pathway.

DVT Care Pathway - Overview

Please click the relevant flowchart box to be taken directly to textual information.

Red Flags
1. VTE during pregnancy and the puerperium (6 weeks post-partum).
2. VTE in IV drug users.
3. If you suspect DVT, always assess the patient for pulmonary embolism (PE) as well.
4. Apparently isolated superficial femoral vein thrombosis is almost always associated with proximal vein DVT.
AEC Upper Limb DVT Pathway

To access the AEC pathway for Upper Limb DVT please follow the link to the Urgent Care section.


A diagnosis of DVT is usually suspected in patients who complain of a painful swollen limb. However, the clinical picture can vary widely and none of the clinical features are sufficiently specific to be a diagnostic. Less than a third of patients referred for tests after initial history and clinical examination prove to have a DVT.

  • Pain or tenderness of the leg
  • Swelling of calf or leg
  • Pitting oedema
  • Palpable venous thrombosis
  • Increased temperature in the leg
  • Fever
  • Discoloration or erythema of the leg
  • Venous distension

  • Recent surgery
  • Recent injury or trauma
  • Previous DVT
  • Intravenous drug misuse
  • Recent immobility (> 24 hours)
  • Long haul air flight
  • Obesity or excess weight
  • Oestrogen therapy
  • Underlying malignant disease
  • Family history of thrombosis
  • Known thrombophilic defect
  • Pregnancy
Differential diagnosis

Consider the following in your differential diagnosis:

  1. Physical trauma including calf muscle tear or strain, muscle haematoma, sprain or rupture of a tendon, fracture.
  2. Vascular disorders of the leg including superficial thrombophlebitis, post-thrombotic syndrome, venous obstruction, congenital vascular abnormalities, vasculitis, heart failure.
  3. Causes of peripheral oedema including cellulitis, ruptured Baker's cyst, stasis oedema, obstruction of lymph drainage, septic arthritis, cirrhosis, nephrotic syndrome.



Please click the relevant flowchart box to be taken directly to textual information. 


  • All patients presenting with suspected DVT should be assessed using a modified Wells Clinical Probability Scoring Tool to determine whether they should have an USS and D-dimer test(click on the links for the referral forms and more information)
  • If both legs are affected, score the more severe leg.
  • If suspected DVT, actively exclude a PE (if necessary using the two-level PE Wells score .

Two Level DVT Wells Score to access Table please follow this link)

Practice Point

Ultrasound scan (click on link for criteria) has become the investigation of choice in the diagnosis of DVT. It will detect more than 94% of proximal DVTs (i.e. popliteal vein and above). It is less sensitive for calf vein thrombosis (about only 60% are detected) but pulmonary embolism from this site is rare and unlikely to cause significant haemodynamic disturbance even if it occurs. Patients who are ‘likely’ to have a DVT and who have a negative scan initially are rescanned after 1 week to detect proximal extension of any thrombus, in recognition of the fact that only 60% of calf vein thromboses are detected on USS.

Book the DVT USS via the ICE online booking system. If you have any concerns, contact the ultrasound department at GHFT

D-dimers are a specific breakdown product of cross-linked fibrin, released during clot dissolution or fibrinolysis. The main object of the D-dimer test is to detect situations of thrombin activation and in vivo fibrin formation. Venous thrombotic embolism results in raised levels of D-dimers. The specificity of the assays for DVT is variable and depends on the patient population. It is important to understand that false positive results are common in older patients, patients with infection or cancer and in post-surgery patients. D-dimer is a ‘rule out’ test with poor specificity and a high false positive rate.

Note that a D-dimer test can become negative two weeks after a clot occurs, so all patients with possible DVT who have had symptoms for two weeks or more must be scanned.

  • Arrange D-dimer test (at point of care if available, same or next day if not) and make sure patient has access to prescription/medication so that a positive result can be acted upon.
  • D-dimer negative: advise patient that DVT is unlikely.
  • D-dimer positive:
    • Prescribe interim 24-hour dose of Fragmin or NOAC and arrange proximal vein USS at the earliest opportunity.
    • USS positive: diagnose DVT and initiate or continue definitive treatment.
    • USS negative: discontinue treatment, advise patient that DVT is unlikely.

  • Check for signs of a PE. Apply the two-level PE Wells score.  If PE likely refer via SPCA to Ambulatory Emergency Care (AEC).
  • Once PE ruled out, weigh patient and arrange:
    • D-dimer test (include patient’s telephone number on request for contact by OOHs clinicians if positive)
    • U+Es (to exclude significant renal impairment - eGFR <30)
    • Full Blood Count and Clotting (to exclude severe anaemia thrombocytopenia or clotting problems)
    • Proximal vein USS
  • Prescribe interim 24-hour dose of Fragmin or NOAC.  If more than 4 hours before scan give Rx for 6 x 15mg Rivaroxaban and start one 15mg dose b.d.
  • Give patient CCG leaflet explaining pathway & further info if wanted.  Explain to the patient what might happen if the D-dimer blood test is positive.
Management (Primary Care and Community)

  1. Elevation of the leg (supported at the heel) when at rest may help reduce swelling but early mobilisation is advised.
  2. Simple analgesia may be indicated for discomfort and should be offered.
  3. Encourage good hydration.
  4. Avoid venous obstruction wherever possible and advise the patient to avoid harm from constricted clothing.
  5. Treatment with (i) twice daily Rivaroxaban or (ii) daily LMWH with Warfarin anti-coagulant therapy started as indicated. See the BNF for patient weight-related LMWH dosages.

Click this link to be taken to the Prescribing section for further information.

Key Point

Patients with a diagnosed unprovoked DVT will need further assessment for a possible underlying cause.

  1. If over 40 years of age – always investigate for cancer.
  2. If without cancer –  consider test for antiphosphlipid antibodies but thrombophilia testing rarely indicated or helpful (BMJ Diagnosis and Management of Heritable Thrombophilias)
  3. If there is a 1st degree relative who has had DVT or PE, consider test for hereditary thrombophilia – see above.

Do not offer thrombophilia testing to 1st degree relatives of people with a history of DVT or PE and thrombophilia.

  • Adults only (> or = to 18 years)
  • Patients with a calf vein DVT or patients with a proximal DVT (above popliteal vein and into the femoral vein) which is not compromising the leg, and which is not associated with pulmonary embolus.
  • Patients who are able to understand the instructions for anti-coagulation or who have carers who can manage this for them.

Follow link for Patient Leaflets for DVT.

  • Patients with a thrombus extending above the femoral vein.
  • Patients presenting with pulmonary embolus.
  • Patients with risk factors for anti-coagulation therapy, i.e. patients with a known history of bleeding disorders.
  • Patients who are totally immobile which precludes ambulatory care at home.
  • Patients with other medical conditions necessitating admissions.
  • Pregnancy.

GPs will administer Rivaroxaban or LMWH and ensure (as far as reasonably possible) that the patient is complying with the prescribed anti-coagulation therapy and that symptoms are controlled. In some cases, where appropriate and safe, the patient may be willing to self-administer the LMWH. However, the participating GP practices will retain responsibility for the overseeing of the patient until discharged from the service.

Unless there are clear contraindications anticoagulant treatment should be followed by low dose prophylactic Aspirin.


Duration of anticoagulation

Evidence on this is poor – see Circulation 2014;130:2343-2348 – but 3-6 months for a first DVT is the accepted treatment followed by low dose prophylactic Aspirin.

Duration of anti-coagulation for first episode
  Popliteal or above Below knee
Reversible provoking factor (e.g. surgery, long haul flight, OCP) 3/12 6/52
Unprovoked or non-reversible provocation (e.g. cancer) 3-6/12 3/12
  • Patients with a post-operative calf vein thrombosis (thrombus detected up to 3 months following surgery) without any risk factors can be treated with anti-coagulants for 4-6 weeks.
  • Calf vein thrombosis in non-surgical patients without any risk factors (thrombus detected in the calf veins only) can be treated for 13 weeks.
  • Patients with proximal deep vein thrombosis (thrombus from the knee upwards, including popliteal vein) can be treated for 13-26 weeks.
  • Patients with recurrent DVT will remain on oral therapy indefinitely.
  • Routine INR testing is not currently available out-of-hours or at weekends/bank holidays. Therefore depending on which day of the week the patient is first diagnosed, it may be necessary to maintain the patient on LMWH for more than 5 days in order to start the Warfarin on a suitable day.
  • In all cases, the GP/medical officer responsible for prescribing Warfarin must ensure that the patient and (if involved) the community nursing team have clear instructions on the correct dose of Warfarin to be taken.

Please see 'National and NICE Guidance' Section for additional information.


Compression hosiery

Once the immediate treatment for the DVT is completed and patients are no longer complaining of tenderness or swelling, they should be advised to wear graduated support hosiery as a measure to reduce the incidence of post-thrombotic syndrome. The benefit of wearing compression hosiery should be explained to the patient in order to gain optimum compliance.

The patient should be assessed as suitable for wearing Class 2 hosiery (see contra-indications below) and appropriate measurements taken of the affected limb to ensure they are well fitted. Patients should be advised to wear this hosiery during the day but to remove it at night. They should continue to wear the hosiery for a period of 2 years. However, it is acknowledged that not all patients comply with the need to wear compression hosiery for an extended period and the risks of not doing so should be explained to them.

Contra-indications to supplying Class 2 hosiery would be:

  • Recent skin graft
  • Gangrene
  • Leg ulcers
  • Dermatitis
  • Vein ligation
  • Severe arthrosclerosis or any other ischaemic vascular disease
  • Massive oedema of the limb
  • Any extreme deformities of legs (arthritis/osteoarthritis etc.).

If there are no contra-indications, practice nurses should:

  • Take accurate measurements of the affected limb so that the correct size hosiery can be prescribed.
  • Prescribe below knee Class 2 hosiery.
  • Assess the patient or carers for their ability to safely apply the hosiery.
  • Show patient/carer the correct method of application.
  • Advise that the hosiery will (under normal conditions) need to be replaced every 3 months in order to maintain its compression functionality
Record Keeping and Audit

Clinical Term Read Code V2 Additional Notes (if applicable) Read Code V3
Suspected deep vein thrombosis (DVT) 1JH..   XaNfd
Wells deep vein thrombosis clinical probab 388z. Wells clinical assessment tool XaN7m
D-dimer level 42Qf D-dimer test X76wX
Venogram normal 55C2. Venogram normal 55C2.
Venogram abnormal 55C3. Venogram abnormal 55C3.
Deep vein phlebitis and thrombophlebitis of the leg G801. DVT diagnosis code XE0VY