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Diagnosis of Thread Veins

Our thorough pre-operative investigation is key to achieving long-lasting success.


The first stage of diagnosing thread veins on the legs is a quick and simple visual check to identify whether red, purple or blue thread veins are present and sufficiently obvious to be worth treating. If they cannot be seen at a quick glance and are not causing any symptoms, and there are not other symptoms of vein disease (tired or aching legs, bulging visible veins, swelling ankles, red or brown stains around the ankles, previous or current thrombophlebitis) then no further investigation may be needed.

However, if treatment is required, the first step is to perform a venous duplex ultrasound scan performed by a Whiteley Clinic-trained Vascular Scientist specialist to find out whether there are any underlying ‘feeding veins’ or hidden varicose veins. This is even more important if any of the associated symptoms listed above are present.

The venous duplex ultrasound scan is performed on the affected leg either with the patient standing, or with the body’s weight placed on the other leg, or with the patient reclining with the legs hanging down. It is impossible to perform a proper duplex ultrasound scan if the patient is lying down because the way the scan works is to observe blood falling the wrong way down the vein, due to the influence of gravity.

The Vascular Scientist will follow all of the veins in the legs, particularly those in the area of the thread veins, to build up a picture of the network of underlying veins in the area. The calf or leg below the area being tested will be manually squeezed whilst the duplex ultrasound probe is simultaneously used to observe blood flow in the veins above this point. In normal open veins, blood can be observed to flow upwards towards the heart.

The muscle will then be released to observe whether there is no backwards flow (indicating that the valves are closing normally) or whether there is backward flow – also called ‘venous reflux’ – down the veins (indicating that the valves are not working properly). By performing this test repeatedly on all of the veins in the legs, we can establish which veins are working, which ones are not, and whether the thread veins are being fed by the venous reflux and underlying veins.

Following The Whiteley Protocol®, a decision can then be made by the clinic specialist whether to treat the underlying veins first or whether the thread veins can be treated without any other procedure.