USP 861 Determining the Diameter of Surgical Sutures

The USP 861 standard, designed by the United States Pharmacopeia (USP), regulates the principles for determining the diameter of surgical sutures. The measuring equipment used to determine the diameter of surgical sutures is mechanical or electrical and is equipped with a direct read dial, a digital readout or a printed readout.

Surgical threads (surgical threads) come in various sizes. Stitches are grouped in different sizes according to the diameter of the thread. The classification established by the US Pharmacopoeia (USP) is widely accepted worldwide. However, some European countries use the metric classification system of surgical threads by thread size.

The higher the diameter of the surgical thread, the stronger the tensile strength. This classification helps all manufacturers around the world to adopt uniform standards. It also helps surgeons select and request the correct thread size required for a particular procedure. For example,

• USP size 7 corresponds to synthetic thread metric number 9 (0.900 - 0.999 mm)
• USP size 0 corresponds to synthetic thread metric 3.5 (0.350 - 0.399 mm).

A surgical thread diameter is one of the criteria involved in its selection and applies to both needle and thread. The diameter or gauge is expressed differently depending on the reference pharmacopoeia (EP or USP) and there is a wide range of diameters.

Surgical suture material can be made from a single filament or several filaments:

• Monofilament. These threads are an attractive option due to their strength, low tissue entrainment and low propensity to spread infection.
• Multi-filament. Compared to monofilament yarns, the spaces between the fibers facilitate the spread of pathogens along the fiber and have a higher risk of promoting infection.
• Not absorbed. In the past, these sutures have played an important role in the development of surgical procedures. It is still used today, especially in cardiovascular surgery. Non-absorbable sutures offer long-lasting support as they stay permanently in the body.

Our organization, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors, also provides testing services for determining the diameter of surgical sutures, within the scope of the USP 861 standard, with its trained and expert staff and advanced technological equipment.