In the matters related to medical device procurement and registration, the "2.5 size 22mm" of the Tuohy epidural needle is a non-standard general description. It needs to be converted into the standardized parameters specified in the registration certificate to complete the approval and order. The domestic NMPA registration and international common marking method is: Gauge (G) + Length (mm/inch) + Tip Type (Tuohy/Huber curved). In this case, it should be written in a standardized way: Epidural Needle, Tuohy Tip, 22G (Outer Diameter 0.7mm), 22mm (≈0.87 inch), with/without wings, sterile, single-use.

It should be noted that if "2.5" is converted according to French units: 1Fr = 0.33mm, 2.5Fr ≈ 0.83mm OD, which is slightly larger than 22G (0.71mm). Some European manufacturers label pediatric/micro-sized Tuohy needles with "Fr". When purchasing, it is necessary to check the actual outer diameter and match it with the corresponding catheter specification - usually, for epidural catheters, the standard is 18G to 20G for guidance, while micro catheters may be labeled as 24G to 27G. Both must be verified for compatibility. Mistaking a 22G Tuohy needle for a 20G standard epidural catheter will result in inability to insert.

In terms of the quality system, Tuohy products must have an ISO 13485 medical device quality management system certificate, a product CE Mark (for export to the EU) or a NMPA registration certificate (for listing in China), and the sterilization method is ethylene oxide (EO) with a verification report on the aseptic assurance level (SAL 10⁻⁶). The packaging should clearly indicate: batch number, expiration date, gauge/length color marking (22G is usually black or according to the manufacturer's color ring), whether it contains a stylet (an integrated plastic stopper to prevent tissue blockage), whether it is latex-free and DEHP-free.

In centralized procurement and hospital bidding, the Tuohy needle is often included as a component of "anesthesia puncture kit / epidural puncture kit". The 22G/22mm ultra-short model purchased separately is commonly seen in pediatric surgery, pain clinics, or specialized centers when applying for supplementary orders. Suppliers need to be able to provide full traceability of BOM materials - including metallurgical reports of 304/316L stainless steel materials, records of electrolytic polishing and ultrasonic cleaning processes, and COA (Certificate of Analysis) for puncture force/leakage/duct passage detection of the finished product. This is a key point for inspection in high-end medical institutions.

When making procurement and technical assessment, it is required that the manufacturers provide the following information:

1. Whether the applicable scope of the registration certificate includes "epidural anesthesia/sacral block";
2. Confirmation of the needle tip geometric dimensions to verify the shape of the curved side hole;
3. Summary of the biocompatibility (ISO 10993) test;
4. Whether the clinical user manual indicates the compatible specifications of the microcatheter.
5. Only when all the above documents are met can they be included in the list of qualified suppliers.