A range of elastic hosiery is specified by the British Standards Institution (BSI). Stockings are classified according to the maximum pressure at the ankle and the pressure gradients at calf and thigh (see Figure 3). Standard methods are in place for batch testing of these garments, and an important attribute is durability. Stockings have to maintain 85% of their original pressure after 30 washes in accordance with the manufacturer’s instructions.

Classes

There are three different classes of compression hosiery. Each class differs with regard to the level of pressure exerted. The classes, as described by the National Health Service Drug Tariff (2001), are as follows:

Class 1

This class provides light (mild) support and produces compression of 14mmHg -17mmHg at the ankle.

Indications:These stockings are for superficial or early varices and those occurring during pregnancy.

Class 11

These stockings provide medium (moderate) support. Compression at the ankle is 18mmHg – 24mm Hg.

Indications: They are generally used for: varices of medium severity, ulcer treatment and prevention of recurrence, mild oedema, varicosis during pregnancy, and for soft tissue support.

Class 111

These stockings provide strong support. Compression at the ankle is 25mmHg – 35mmHg.

Indications: This class is used for: gross varices, post thrombotic venous insufficiency, gross oedema, ulcer treatment and prevention of recurrence, and soft tissue support.