Function Testing, Damage, and Lubrication

An instrument can come out of the sterilizer perfectly sterile and still be dangerous. A dull scissors crushes instead of cuts, a cracked insulation layer can let electrical energy escape, and a loose jaw can fail at the worst possible moment. Function testing is how you catch that before the set ships.

After cleaning and visual inspection, you confirm the device still does its job: blades cut, jaws align, ratchets hold, insulation is intact, and nothing is missing. The test has to match the working part, and it has to use the right material.

One rule runs through this whole topic and shows up often on the exam: a failed test controls the device’s status, and being short a replacement never changes that. Always confirm the current device, tester, and lubricant instructions.

What is instrument function testing?

Function testing is a set of defined, device-specific checks that confirm a clean instrument still performs as intended before assembly. Depending on the device it can cover alignment, sharpness, movement, ratchet action, jaw grip, insulation, completeness, and accessory fit — each checked with the correct method and test material the manufacturer specifies.

How do you match the test to the working part?

Every family of instruments has a function the user depends on, and each has a clear reason to be rejected. Use the correct test material, not a shortcut like paper or a glove, because informal testing can damage an edge or miss a defect.

Test the function across its full required range. A scissors that cuts at the tip but folds the test material near the heel has not passed — a partial pass is a failed result when the approved test requires complete performance.

When and how should you lubricate?

Lubricant has a narrow, specific job. Instrument lubricant is a compatible product, commonly water-soluble, used as directed to support motion and protect surfaces. Apply it only when the IFU permits, and only at the location, stage, and amount the instructions state. It goes on after cleaning is confirmed, and you retest movement afterward.

What lubricant does not do matters just as much. It treats permitted friction; it does not repair dull edges, misalignment, cracked insulation, loose parts, or corrosion. Using it to quiet a stiff, damaged joint only hides the defect.

Watch: A Short Video Walkthrough

W.D.Y.D CSP walks through this topic clearly in a few minutes. It pairs well with the reading above:

A device fails and there is no spare — now what?

A laparoscopic instrument fails insulation testing near its distal end, and no replacement is immediately available. The shortage is real, but it does not change the result. Work it in order:

1. Read the evidence: the approved test found an insulation defect near the working end.
2. Apply the rule: a failed test controls the device’s status, and a shortage does not change the acceptance criteria.
3. Remove and clearly identify the instrument so it cannot go back into use.
4. Document the defect and route it for approved repair or replacement.
5. Communicate the shortage through the approved set process so the clinical team can plan.

An insulation defect is a break that may let unintended electrical energy escape, so it is never acceptable to leave in a set — even for one urgent case.

Why can’t a duplicate or a bench fix rescue a failed instrument?

Two tempting shortcuts fail for the same reason. Keeping a dull or misaligned instrument because another one is present does not make the damaged one safe; a duplicate does not change the failed item’s acceptance criteria. Adjusting jaws at the assembly station can worsen the defect and is not an approved repair. When a hemostat’s jaws do not align, it leaves service for documented repair. When scissors fold the test material along the blade, they are removed, documented, and routed for repair or replacement — passing at a single point does not satisfy a test that requires reliable cutting across the whole blade.

Practice questions

1. Scissors cut at the tip but fold the approved test material near the heel. What should the technician do? (A) Keep them for fine work   (B) Remove, document the failed full-blade test, and route for repair   (C) Lubricate the pivot and accept them   (D) Swap in unverified scissors and fix the count later
2. A hemostat’s jaws do not align when closed. What should happen? (A) Adjust the jaws at the bench and retest   (B) Lubricate the box lock and accept it   (C) Remove it from service for documented repair   (D) Keep it as a spare
3. A clean hinged instrument moves stiffly and its IFU permits water-soluble lubricant. What is appropriate? (A) Apply household oil   (B) Lubricate before confirming it is clean   (C) Use silicone spray from maintenance   (D) Apply the approved lubricant, then retest movement
4. A laparoscopic instrument fails insulation testing and no spare is available. What controls the decision? (A) The shortage, so include it   (B) The failed test, so remove and route it for repair   (C) The urgency of the case   (D) The external indicator
5. Which test material should confirm a scissors’ cutting action? (A) A paper towel   (B) A glove   (C) The approved test material   (D) The technician’s fingernail
6. What can lubricant correctly address? (A) A cracked insulation layer   (B) Misalignment   (C) Permitted friction after cleaning   (D) A dull edge

Answers: 1 (B) — passing at one point does not satisfy a test that requires cutting across the blade. 2 (C) — a duplicate does not make a misaligned instrument safe, and bench adjustment can worsen it. 3 (D) — compatible lubrication after cleaning supports function, then movement is retested. 4 (B) — a failed test controls status; a shortage does not change acceptance criteria. 5 (C) — the approved test material is required; paper, gloves, or skin are not. 6 (C) — lubricant treats permitted friction, not damage like dullness, misalignment, or cracked insulation.

Where This Fits in Your CRCST Prep

This topic is one lesson in the Preparation & Packaging group of the free CRCST Study Hub. The hub maps every exam topic in order, from the first-day basics through the full-length practice simulations, so you always know what to study next.

Related lessons in this group:

• Prep-Area Safety, Equipment, and Workspace Readiness
• Visual Cleanliness Inspection
• Instrument Identification and Count Sheets
• Assembly, Positioning, Protection, and Organizers
• Chemical Indicators and Integrators