Preparation, Packaging, Storage, and Distribution
Between cleaning and sterilization sits the work that determines whether an instrument is safe and functional in a surgeon's hand, and whether a sterile package stays sterile until it is opened. This chapter covers instrument inspection and functional testing, set assembly, the three packaging systems and their rules, labeling and lot control, the difference between event-related and time-related shelf life, sterile storage conditions and clearances, and transport and inventory practices.
Inspection and Functionality Testing
Every instrument is inspected individually under lighted magnification before it is assembled into a set. The technician looks for residual soil in serrations and box locks, cracks, pitting, corrosion, worn or chipped tips, misaligned jaws, loose pivot screws, and stiff or sticking hinges. Mechanical cleaning reduces bioburden but does not guarantee that a specific device came out clean and functional, which is why item-by-item inspection cannot be replaced by a quick visual scan. Functional testing is device specific: scissors are tested by cutting the appropriate test material with the distal third of the blades, where dullness appears first; needle holders are checked for secure grip on a suture needle without slippage; ratcheted instruments are tested by closing to the first ratchet and tapping to confirm they hold; and clamps and forceps are checked for jaw alignment and tip approximation. Instruments that fail are removed from service and sent for repair rather than returned to the set. Lubrication, when the manufacturer specifies it, uses a water-soluble, steam-penetrable instrument lubricant. Petroleum-based oils and industrial sprays are prohibited because they form a barrier that blocks sterilant contact and can leave toxic residues.
Set Assembly
Assembly balances three goals at once: the set must sterilize reliably, arrive functional and complete, and be safe to handle. Hinged instruments are placed open on stringers or racks so that steam reaches the mating surfaces of box locks and ratchets. Heavy items go on the bottom and delicate microsurgical and ophthalmic instruments are protected with tip guards designed to be sterilant permeable. Concave items such as basins and cups are positioned on edge or tilted so that condensate drains rather than pools. Absorbent towels, when used inside a tray, are placed so they do not prevent steam circulation. A count sheet accompanies the set and is used to verify contents against the standardized list, and any substitution or missing item is documented. Total set weight is kept within recommended limits, commonly around 25 pounds including the tray and containment device, because heavy sets retain more condensate, dry poorly, and create lifting injuries. Tray liners and mats used to absorb condensate must be approved for that purpose and must not block perforations.
Packaging Systems
Three packaging systems dominate: sterilization wrap, peel pouches, and rigid containers. Every one of them must allow sterilant to enter and reach the contents, provide a barrier against microbial entry after processing, permit aseptic presentation at the point of use, and survive normal handling and transport. Sterilization wrap is applied by either the sequential method, which uses two separate wrappers applied one after another, or the simultaneous method, which uses a bonded two-ply wrapper applied once, using either the envelope fold or the square fold. Wrap must be inspected for holes and applied without excessive tension. Peel pouches are used for small, lightweight, single items. The pouch is sized so the contents do not stress the seals, the item is positioned so the handle presents first when opened, and double pouching is done only when the pouch manufacturer validates it. Rigid containers depend on correct, unused, properly seated filters and on intact gaskets, valves, and latches, all of which are inspected before every use, with a tamper-evident lock applied after assembly so users can see at the point of use that the container has not been opened. Containers are deliberately not airtight, because steam must be able to enter.
Labeling and Shelf Life
A sterilized package carries a label with a lot control number identifying the sterilizer, the cycle or load number, and the date, plus a description of the contents and the identity of the person who assembled the package. This is what makes traceability and targeted recall possible, and it also lets users select the correct package without opening it. Shelf life is approached in one of two ways. Under time-related sterility, an arbitrary expiration date is assigned and the package is reprocessed when that date passes. Under event-related sterility, which is the prevailing approach, a package is considered sterile until a specific event compromises the barrier. Events include moisture or wetness, tears, punctures, broken or open seals, compression damage, dropping on the floor, and excessive or contaminated handling. This shifts the responsibility to the user, who must inspect every package before opening it. Event-related sterility does not mean packages are ignored: stock is still rotated first in, first out so that packages do not sit indefinitely accumulating handling wear, and any package with a compromised barrier is removed from inventory and fully reprocessed from the beginning. Taping over a tear does not restore a sterile barrier and conceals the defect from the next user.
Sterile Storage, Transport, and Inventory
Sterile storage is a controlled environment designed to protect packaging integrity. Temperature should not exceed about 75 degrees F (24 degrees C) and relative humidity should not exceed about 60 percent, with a minimum of 4 air exchanges per hour and positive pressure so clean air flows outward. Traffic is restricted and the area is kept clean and dry. Shelving clearances are frequently tested: bottom shelves are kept 8 to 10 inches off the floor so that wet mopping and floor contamination do not reach packages, at least 18 inches of clearance is maintained below sprinkler heads to preserve fire suppression coverage, and packages are kept about 2 inches away from outside walls where condensation can form. Closed cabinets are preferred for low-use and high-value items. Corrugated cardboard shipping cartons are prohibited because they shed particulate, harbor insects and moisture, and arrive from uncontrolled warehouse and dock environments; supplies are removed from shipping containers in a separate breakout area. Transport uses closed or covered carts that protect packages from moisture, dust, and physical damage, and handling avoids crushing or compression that can breach a barrier invisibly. Inventory rotates first in, first out, with newly processed packages placed behind existing stock.
Last updated: July 2026