Deep Vein Thrombosis DVT Pathway: Assessment, D-dimer & Referral for BNSSG

Updated forms can be found on Remedy

Please refer to Remedy for BNSSG DVT information, including the BNSSG DVT Pathway and referral form. Full background on assessing possible DVT is available via the NICE Clinical Knowledge Summaries.

Typical signs and symptoms

Consider DVT if typical symptoms/signs are present, especially when risk factors exist:

Pain and swelling in one leg (occasionally both legs).
Tenderness, changes in skin colour or temperature, and vein distension.

Scope: Guidance for assessment and management of patients presenting to SevernSide during the out-of-hours (OOH) period.

Initial management in OOH

Clinical judgement is central. Any patient may be referred directly for ultrasound if clinically appropriate.

Take a history (include risk factors and differentials), arrange a face-to-face assessment, and examine the patient.
If DVT is suspected, complete and record the Two-level DVT Wells score to estimate clinical probability.

DVT Wells score ≥ 2

Perform D-dimer and other bloods. Note: a negative D-dimer in this group does not remove the need for a scan. If the scan is inconclusive, a negative D-dimer means a second scan is not required.
Refer to Cohese Healthcare for ultrasound.

DVT Wells score 0–1

Perform D-dimer and other bloods (see D-dimer section below).
If D-dimer is positive, refer to Cohese Healthcare for ultrasound.

Two-level DVT Wells score < 0

D-dimer or referral usually not required.
Low suspicion of DVT; another diagnosis is more likely.
Review diagnosis and repeat Wells score if the clinical condition changes.
If clinical suspicion remains, direct referral for ultrasound is appropriate.

D-dimer

Near-patient testing

Near-patient D-dimer kits give a result in about 15 minutes. Kits (lancets, diluent, testing strip) and written instructions are in the DVT box at each base. See the quick reference guide for how to test. Record each test in the D-dimer record book (include the Adastra number and date) so stocks can be replenished.

Do not perform D-dimer in:

Wells score < 0
Pregnancy
Up to 2 weeks post-operative
Symptoms for ≥ 2 weeks
Current inflammatory process

Referrals to Cohese Healthcare for ultrasound (from IUC during OOH)

Cohese Healthcare delivers the community DVT service for BNSSG.

Complete the referral form on the Remedy DVT page and include an up-to-date patient phone number so Cohese Healthcare can arrange the scan.
Email the referral to cohese.dvt@nhs.net.
How to send a referral from SevernSide: see guidance.
Provide the patient information leaflet (print or text link): Cohese Healthcare community DVT pathway leaflet (document branding may still reference GP Care).

Red flags – refer immediately to secondary care

Suspected diagnosis of pulmonary embolism.
Patients under 18 years (≤15 to paediatrics; 16–17 to adult services).
Suspected upper-limb (arm) DVT.
Other acute disease process or patient acutely unwell requiring admission.
Weight > 165 kg.

Mobility/hoist: As of May 2024, Cohese Healthcare can accept patients who need a hoist, but not all clinics have one. There may be a wait for a suitable clinic, or refer to secondary care.

Further information on secondary care DVT services is available on Remedy, including referral details for NBT, Weston and BRI (in and out of hours).

Pre-diagnosis anticoagulation

Anticoagulate with oral DOAC treatment (Apixaban or Rivaroxaban) or parenteral treatment (e.g. Enoxaparin), or issue standby prescriptions:

Do not use Edoxaban initially; it requires ≥5 days of parenteral anticoagulant first.

Anticoagulate until the venous D-dimer result is available and a clinician has acted on it,

While awaiting ultrasound if not available within 4 hours of referral.

Prescribe the minimum needed to cover until the scan (e.g. 7 days).

Patients already on anticoagulation

Rivaroxaban: increase to 15 mg bd.
Apixaban: increase to 10 mg bd (if CrCl > 30).
Edoxaban, Dabigatran, Warfarin: cannot up-titrate; consider switching to LMWH.
Clexane (Enoxaparin) OD: switch to Clexane BD.
Already on Clexane BD: consider admission for IV heparin while awaiting scan.

Patients requiring Clexane injection during OOH

Most patients awaiting a scan or with confirmed DVT will be managed with oral anticoagulation. If Clexane is required and the patient/carer cannot administer it, Cohese Healthcare may refer for an IUC base appointment for administration via the Professional Line.

SVT (superficial venous thrombosis) – referral and treatment

See the SVT Treatment pathway for the flow chart and referral criteria.
Patients needing a leg ultrasound for suspected SVT can be referred to Cohese Healthcare (exclusions as for DVT).
SVT < 3 cm from a deep-vein junction: treatment-dose anticoagulation for 3 months.
SVT > 5 cm long, not within 3 cm of a deep-vein junction: prophylactic-dose anticoagulation for 6 weeks.
SVT not meeting the above criteria: no anticoagulation; manage in primary care with NSAIDs and/or a topical agent.
See NICE guidance for SVT.

Weekday Professional Line – team information

NBT: If not suitable for Cohese Healthcare, there is no dedicated DVT clinic; use Gate 36 (SDEC), Southmead.
BRI: If not suitable for Cohese Healthcare and Wells ≥ 2 or raised D-dimer, refer by phone to Thrombosis Clinic (0117 342 4684). Hours: Mon–Fri 09:00–17:00; Weekends & bank holidays 09:15–13:00.
WGH: If not suitable for Cohese Healthcare, patients are usually seen on SDEC.

?DVT with additional symptoms suggestive of PE should be referred for acute hospital admission.

Most ?DVT requiring a scan (without PE symptoms) should be directed to the BNSSG-wide community DVT service run by Cohese Healthcare.

Prison patients can be accepted in community DVT clinics. Prison clinicians should complete the referral form available here (site branding may still reference GP Care).

Cohese Healthcare – exclusion criteria

Please note: Patients requiring hoisting can now be seen by Cohese Healthcare. One Bristol clinic and the Weston-super-Mare clinic can accommodate hoisted patients.

If the patient is not suitable for Cohese Healthcare, arrange secondary care assessment. Aim for early-day arrival (scans typically not after 16:00–17:00). If the referral is taken later in the day, anticoagulate and arrange hospital arrival the following morning.

Particular scenarios

Proximal DVT: Acceptable for Cohese Healthcare; refer to Vascular if needed.
Wheelchair/bedbound: Accepted. Two clinic locations can hoist patients onto the couch for scanning.
In a cast: Not scannable in community clinics; refer to Orthopaedics for cast removal and assessment.
Pregnant patients: Accepted.
Post-partum: Accepted. Usual advice: Clexane 1.5 mg/kg OD pre-scan (DOACs contraindicated post-partum and during breast-feeding).
Prison patients: Accepted, noting potential transport issues for timed appointments.

Bank holidays and weekend capacity

NICE recommends scans within 24 hours. In practice this may be difficult over weekends and bank holidays. Cohese Healthcare usually runs Saturday clinics on bank-holiday weekends. If clinics are full and scan delay is a few days, options include:

Anticoagulate and wait for a community scan. Baseline FBC/U&E/LFT/clotting may be needed if not done recently (can be done in IUC if not possible in the GP surgery). Do not delay starting anticoagulation while awaiting blood results. Provide clear safety-net advice.
Arrange scanning in secondary care – discuss with AEC consultant (NBT/WGH) or Thrombosis Nurses (BRI) as scanning may be limited over bank-holiday weekends.

Branding note: GP Care is now Cohese Healthcare. Some links, documents and the service email address may still reference GP Care during the transition; referral routes and clinical processes remain unchanged.