Thrombosis Knowledge Centre
Diagnosis
Diagnosing Deep-vein Thrombosis
Accurate diagnosis of DVT is indispensable. In daily practice, it is generally based on the use of ultrasonography, a non-invasive, rapid and cost-effective method.
Screening tests
- D-dimers: if normal, rule out acute DVT
- Plethysmography: records the changes in the size of the limb due to tissue fluid or pooled blood in the veins
Ultrasonographic image of a thrombus in popliteal vein:
Confirmatory tests
- Venography:
- Gold standard
- But invasive and contraindicated in some patients (allergy to iodinated contrast products, renal impairment)
- Indicated if non-invasive tests:
- Not feasible,
- Equivocal, or
- Negative but high clinical probability
- Ultrasonography:
- Best non-invasive method for proximal DVT, but less sensitive for distal DVT
- 3 techniques:
- Compression ultrasonography (CUS): records the compressibility of the vascular lumen under gentle probe pressure
- Duplex ultrasonography: same as the above + evaluation of blood flow by measuring the pulsed Doppler signal
- Colour flow duplex imaging: same as the above but in colour to more easily identify the veins
- Serial CUS: to determine the potential extension of a suspected distal DVT to proximal veins
- Various combinations of the tests described above may be included in the diagnostic strategy for DVT
- Spiral computed tomography venography and magnetic resonance imaging: not currently used in routine practice
What is the diagnostic strategy for DVT?
See below for an example of a diagnostic algorithm for suspected DVT
Kyrle and Eichinger. Lancet 2005;365:1163-74