Leg Vein Ultrasound (DVT study, both legs)

What it is

A clot in a deep leg vein matters mainly because of what it can do next: a piece can break loose and travel to the lungs. So this test is built around one decision, and it needs to be reliable. The sonographer works down the leg pressing the probe firmly at short intervals. A normal vein collapses flat under that pressure; a vein with clot inside it does not. That simple manoeuvre, more than the picture itself, is what finds a clot. Doppler is used alongside it to show whether blood is moving through the vessel and how it responds to breathing and to squeezing the calf. This particular code is the complete bilateral study — both legs worked through in full.

Why it is done

• To find or rule out deep vein thrombosis in a leg that is swollen, painful, warm or discoloured
• To check for a clot source after a clot has been found in the lungs
• To investigate leg swelling that has no obvious explanation
• To look at valve function in veins that are not draining properly
• To re-examine a leg where a clot was previously found, to see whether it has changed

What to expect

There is no preparation and nothing is injected. Patients undress the legs, lie on an exam table, and warm gel is applied. The sonographer presses the probe along the groin, thigh, behind the knee and down the calf, repeatedly and firmly — that pressure is deliberate and can be uncomfortable over a tender area, though it should be reported if it becomes painful. The Doppler portion makes an audible whooshing sound, which is expected. A full study of both legs typically takes something like half an hour to an hour. Because this is often an urgent question, results are usually available to the ordering doctor the same day, and a radiologist or vascular physician reads the images rather than the sonographer giving an answer in the room.

Questions worth asking

• Was both-leg imaging ordered, or one leg? The bilateral complete study is a separate, higher-priced code than a single-leg study, and a limited study is a third code again.
• If this is being done in an emergency department, the facility fee is usually the largest number on the bill. Ask whether an urgent outpatient vascular lab appointment is an option.
• Hospital vascular laboratories and freestanding centres often price this differently. Ask which one your order sends you to.
• Ask whether the interpreting physician is in network — the lab and the reader can be contracted separately.
• If the study is repeated in a week or two to recheck a finding, confirm whether the follow-up is billed as a complete study again or as a limited one.