This Wells score for DVT calculator determines how likely a deep venous thrombosis is based on patient clinical criteria. Discover more about DVT and how the scoring tool works below the form.


Lower limb trauma, surgery or plaster

Immobilization for more than 3 days or surgery within last month

Tenderness along femoral or popliteal veins

Entire limb swelling

Non varicose dilatation of collateral superficial veins

Calf more than 3cm bigger circumference, 10cm below tibial tuberosity

Pitting edema

History of confirmed DVT

Malignancy

Intravenous drug use

Alternative diagnosis more likely than DVT

How does this Wells score for DVT calculator work?

This is a health tool used to pre test clinical probability of a deep venous thrombosis based on a range of criteria as established in the Wells model. It takes into account the main risk factors for developing DVT such as bed immobilization, surgery or trauma; clinical signs or swelling and edema; as well as the chance of another diagnosis being possible:

1) Lower limb trauma, surgery or plaster – risk of vessel damage and more.

2) Immobilization for more than 3 days or surgery within last month – blood stagnation risk.

3) Tenderness along femoral or popliteal veins.

4) Entire limb swelling.

5) Non varicose dilatation of collateral superficial veins.

6) Calf more than 3cm bigger circumference, 10cm below tibial tuberosity – specific DVT sign.

7) Pitting edema – specific DVT symptom.

8) History of confirmed DVT – patient or family history increase risk.

9) Malignancy – in treatment or not for the past six months is considered a risk factor.

10) Intravenous drug use - particularly involving groin injection.

11) Alternative diagnosis more likely than DVT – such as external venous compression, superficial venous thrombosis, post phlebitic syndrome, inguinal lymphadenopathy, muscle damage or cellulites.

The Wells score proposes the DVT unlikely and DVT likely sorting of the result, therefore the Wells score for DVT calculator displays a result based on the points each answer is awarded and specifies whether a diagnosis of deep venous thrombosis is likely or not.

DVT diagnosis route

This is a very useful risk stratification score and helps the clinician avoid costly clinical determinations such as ultrasound when the probability is low and the D-dimer is negative and in cases where DVT suspicion can be eliminated safely. Consequences of deep venous thrombosis are very serious and with an important mortality percentage if not intervened in time, including pulmonary embolism (PE) and pulmonary hypertension.

The following table describes the several diagnosis pathways according to results in the Wells score and the D-dimer test. A positive diagnosis in ultrasound recommends starting on the main treatment which is anticoagulation; however, there are also associated risks due to possible hemorrhages.

Wells score Interpretation Pre test DVT probability D-dimer Ultrasound
<1 DVT unlikely 5% - low probability negative not necessary
<1 DVT unlikely 5% - low probability positive necessary
1 - 2 DVT unlikely 17% - moderate probability negative not necessary/necessary upon clinical decision
1 - 2 DVT unlikely 17% - moderate probability positive compulsory
>2 DVT likely 35% - high probability negative necessary
>2 DVT likely 35% - high probability positive compulsory

Deep venous thrombosis, causes and warning signs

Is the affection in which one or more blood clots are being formed in the deep veins of the body and these are known as venous thrombosis that usually occurs in the deep large veins of the leg, through the calf or thigh.

As primary signs, these leas to swelling and pain and pose the great risk of pieces of blood clot breaking and traveling through the bloodstream in the lungs, causing a pulmonary embolism. When this happens, an episode of venous thromboembolism VTE is consemnated. Amongst the risk factors there is age, family history of blood clots, malignancy on the basis of chemotherapy damaging blood vessels, heart failure, inactivity due to surgery, trauma or similar.

Blood vessel damage is another cause resultant in blood clots from the narrowing of blockage of the vessel, preventing normal blood flow. Blood vessels can be damaged by their own conditions such as vasculitis or during trauma from broken bones or muscle damage or surgery.

Hormone replacement therapy or the contraceptive pill are said to increase blood clotting risk due to the estrogen intake. There are also infectious or inflammatory conditions to be named as risk factors and also thrombophilia, the condition in which the blood clots easily.

Beside the clinical signs in the Wells score, other symptoms include warming and redness of the skin area, tenderness, discomfort or pain in calves usually but there are also cases in which DVT has no symptoms but poses a great risk of the clot rupturing and causing a pulmonary embolism so deep venous thrombosis is a serious condition that should be monitored carefully, especially in risk group patients.

References

1) Scarvelis D, Wells PS (2006) Diagnosis and treatment of deep-vein thrombosis. CMAJ. Oct 24;175(9):1087-92.
2) Wells PS, Anderson DR, Rodger M, Forgie M, Kearon C, Dreyer J, Kovacs G, Mitchell M, Lewandowski B, Kovacs MJ. (2003) Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med. Sep 25;349(13):1227-35.

06 Jul, 2015 | 0 comments

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