The gauge for determining the diameter of sutures is of the dead-weight type, mechanical or electrical, and equipped with a direct-reading dial, a digital readout, or a printed readout. Use a gauge graduated to 0.002 mm or smaller. The anvil of the gauge is about 50 mm in diameter, and the presser foot is 12.70 ± 0.02 mm in diameter. The presser foot and moving parts connected therewith are weighted so as to apply a total load of 210 ± 3 g to the specimen. The presser foot and anvil surfaces are plane to within 0.005 mm and parallel to each other to within 0.005 mm. For measuring the diameter of sutures of metric size 0.4 and smaller, remove the additional weight from the presser foot so that the total load on the suture does not exceed 60 g.
Collagen Absorbable Surgical Suture
Determine the diameter immediately after removal from the immediate container and without stretching. Lay the strand across the center of the anvil and presser foot, and gently lower the foot until its entire weight rests upon the suture. Measure the diameter of each strand at three points corresponding roughly to one-fourth, one-half, and three-fourths of its length.
Synthetic Absorbable Surgical Suture
Proceed as directed for Nonabsorbable Surgical Suture.
Nonabsorbable Surgical Suture
Lay the strand across the center of the anvil and presser foot, and gently lower the foot until its entire weight rests upon the suture. Measure nonabsorbable sutures, whether packaged in dry form or in fluid, immediately after removal from the container, without prior drying or conditioning.
Measure the diameter of the suture at three points corresponding roughly to one-fourth, one-half, and three-fourths of its length. In the case of braided suture of sizes larger than 3-0 (metric size 2), make two measurements at each point at right angles to each other, and use the average as the observed diameter at that point.
In measuring multifilament sutures, attach a portion of the designated section of the strand in a fixed clamp in such a way that the strand lies across the center of the anvil. While holding the strand in the same plane as the surface of the anvil, place the strand under tension by suitable means, such as by passing the free end of the strand around a cylinder or a pulley and attaching to the free end a weight of about one-half of the knot-pull limit for the non-sterilized Class I suture of the size concerned, taking care not to permit the strand, if twisted, to untwist. Measure the diameter at the designated points on the strand, and calculate the average diameter likewise as directed.
: Radhakrishna S Tirumalai, Scientist
Expert Committee : (GTMDB05) General Toxicology and Medical Device Biocompatibility
USP29NF24 Page 2775
Phone Number : 1-301-816-8339