Inspection & functionality testing
In the clean assembly area, every instrument is inspected — ideally under lighted magnification — for cleanliness, integrity, and function before it is reassembled into a set.
- Check for residual soil, moisture, pitting, rust, cracks, and chips.
- Verify sharpness of scissors and cutting edges using the appropriate test material.
- Confirm box-locks, ratchets, and hinges move freely and that jaws/teeth align.
- Test needle holders for the ability to hold a needle without slipping.
- Inspect insulated devices for breaks in the insulation that could cause patient burns.
Lubrication & care
Hinged and moving instruments are treated with a water-soluble, steam-permeable instrument lubricant ("instrument milk") — never industrial oils, which prevent steam contact and harbor microbes. Lubrication protects the metal and keeps mechanisms working smoothly.
⚠️ Stain vs. rust. Brown/orange discoloration is often a mineral deposit or stain, not true rust. Identify the cause (water quality, detergent residue, dissimilar metals) to correct it. True corrosion (pitting) means the instrument must be removed from service.
Set assembly
Instruments are assembled into trays according to a count sheet / instrument tray list that specifies the exact contents. Correct assembly supports both sterilization and patient safety.
- Place heavy instruments on the bottom and arrange items so steam can contact all surfaces.
- Open all hinged instruments and use stringers or instrument racks to hold them open.
- Disassemble multi-part instruments unless the IFU directs otherwise.
- Place a chemical indicator inside the set in the area considered most difficult for the sterilant to reach.
- Confirm the count and document who assembled the set for traceability.
Tray weight & density
🔑 Tray guidelines
- Total tray weight, including the container, should generally not exceed 25 lbs (about 11 kg) to support drying and ergonomic handling.
- Distribute mass evenly; avoid stacking dense instruments that trap air or condensate.
- Use tip protectors and foam/silicone mats only if they are validated as steam-permeable.
Ready to test yourself?
Reinforce Instrument Processing with quizzes and flashcards.