Verification is an important part in developing medical devices or products, and can really help in making sure the products set out to do what they are supposed to. For instance, take tylenol for example; the purpose of tylenol is to reduce pain and fever, but before they sell it to the public, they have to go through a verification protocol to make sure that it does what it says its gonna do. Not only do we check for its effectiveness but its also essential to check for its safety to the people, its biocompatibility, and its effects to the body when ingested. To check these you may have to go through a number of clinical trials, and lab testings to make sure it meets its requirement. All of these factors needs testing which is all part of the verification process.
There are numerous amounts of medical products that require verification testing. Name a medical device or product that exists, and tell us what you think the verification protocol consists of?
As mentioned in the slides a Verification Protocol consist of: Taking all the outputs, making a test for each one, and listing all the tests in a document. My example of a verification test will be surgical gloves. As mentioned in lecture PDCA- Plan, Do, Check, Act.
1. Make a test for it- Durability-Puncture test (tensile test, and forces and puncture)
2. Check the results-did the glove puncture? No.
3. Did the output pass the test- Yes, no puncture.
If the glove did puncture, then redo the test/change the spec. For example do more tests around design, thickness of glove, material, etc.
Example For Verification process:
If you said in Design Input Requirements " The MRI machine’s electrical system shall operate at 120V at less than 16 amps "
So, for Design Process " Components such as motors, actuators and LEDs rated for 120V that will meet functional requirements will be specified but will not exceed a total of 16 amps during operation"
after the Design output we need to make Verification:
So, the verification method is to test the MRI and measure the power & current
(Verification passes if the power draw is less than 16 amps @ 120V."),
so in Verification Design should states :"The system is tested by measuring the power draw by the system during operation. Verification passes if the power draw is less than 16 amps @ 120V."
After passing verification test you need to Show everything that passed and Stick the tests and test results into the DSD
if didn't pass you should review inputs (DID; Each input must have an output - Each output must be verified and design process)
Multiligamentous Ankle Supports (L1906)
A multiligamentous ankle support provides control of the ankle joint between the medial and lateral malleoli while allowing for dorsiflexion and plantar flexion.
Medicare announced an additional verification for the ankle supports to
1. Include a rigid stirrup and foot plate which provides functional tracking of the ankle with hind-foot and mid-foot stability during ambulation.
2. Include an ankle gauntlet, prefabricated, fitting and adjustment.
For orthopedic devices, such as spinal implants, knee implants, and hip implants, the verification protocols are usually defined by ASTM standards which govern how these devices must be tested. For each type of device, FDA provides guidance on the modes of testing which should be conducted on the device, and ASTM standards dictate how each of these tests must be performed. Any deviations from the standard must be stated and rationalized. The acceptance criteria that the device must meet in order to be deemed acceptable is up to each individual company. Most companies state that the performance of their device to be tested must be equal to or greater than that of a predicate device. Another strategy is to use clinical data from white papers showing the physiological forces that the particular device could be exposed to, and using this data as your acceptance criteria.
The verification protocol of every medical device or products has to consist of doing a test suitable for the desired purpose, then check the results. Based on the output of the test, it is decided if this product or device should move on to the next step or it requires redesigning or modifying. Any verification protocol should include: Purpose including design input, design output being verified, Rationale for the verification design, Measurable acceptance criteria, Materials required, Verification Method/Procedure. Include procedure or reference for evaluation of unexpected test results, Boundary values, must be assessed and included, Data Analysis including validity criteria, if applicable, Statistical methods with references to published
methods, if applicable, and Include method for handling exceptions and outliers.
For example pen injector:
The verification protocol checks for:
1. Flow rate
2. Injection time (i.e., time required to deliver the drug/biological product)
3. Reliability of the mechanism to deliver the drug/biological product
4. Depth of injection
4. Safety features
5. Verification for absence of leakage
6. Verification of non-coring needle (e.g., if the needle is used to puncture a
septum)
7. Needle dwell time (i.e., amount of time that the needle is in the body)
8. Chemical resistance (i.e., data to ensure that the injector and its label are not adversely affected by the recommended cleaning agents)
9. Structural testing at extreme pressure and temperature conditions
10. Force required for assembly
11. Force required to actuate the injector
12. Force required to defeat the needle shield or other safety mechanism
13. Load testing on individual components
14. Needle bond strength (i.e., force required to pull the needle off the injector)
15. Needle penetration force (i.e., force available for needle insertion)
16. Needle deflection angle that causes injector failure (note: this is important if the needle retracts after insertion)
The above tests should include testing of all safety features to ensure they perform as intended. Also, for multiple use injectors, the testing should verify the duration of repeated use.
Siemens Atellica Solution Immunoassay Analyzer:
The extensive verification process of the Immunoassay Analyzer’s generally consists of the instrument and laboratory diagnostic verification. In the instrument verification state, each subassembly must pass its designated test, confirming that it is working as an individual part, before being installed onto the chassis. This step is critical because if a specific subassembly is not working properly, the function and accuracy of the entire instrument is affected. After each of the individual subassemblies are installed to complete the analyzer, the unit as a whole must now pass a verification protocol for each one of the hundreds of analytes that it is advertised to detect. For each output, the diagnostic instrument has to be able to be able to follow a specific sequence of steps for each one and execute properly. All the tests also have a specific range the acceptable values detected must fall between when using a known sample to verify the instrument is preforming correctly. In addition, there exist a certain number of tests performed on each verification analyte to show with significant statistical significance that the instrument is in fact accurate, precise, and reliable.
I choose a Band-Aid. The verification protocol makes sure the inputs matches the outputs. I believe the inputs would be that it sticks to the skin but can be removed without much force and that it doesn't irritate the skin. A verification test would test for this. I think the verification protocol would call to first test the stickiness on the skin. I would probably ask for volunteers and apply a Band-Aid prototype to there skin and remove it the next day. If the Band-Aid didn't stick for most volunteers then I would fail it. If it did, then I would pass it. If it was too hard to remove the next day, I would fail it. I would also look for irritation on the skin of volunteers. If my inputs match my outputs then it would pass.
I work for a company that manufactures handheld blood analyzers. In addition to the verifications performed to ensure the device reads samples within given limits. There are some general functionality input requirements that the device must meet. For example, one of our devices is wireless. So there are input requirements for operational signal strength, expectations for bulk transmission, transmission speed, and applicable encryption types. In the event that there is a firmware upgrade needed for the wireless module, we have to perform certain tests to make sure we still meet these requirements.
Generally these verifications check that the device is able to 1) send and receive accurate results within the defined operating window 2) receive massive amounts of data at once without dropping connection, 3) send data quickly 4) connect, transmit, receive information when connected to WEP, WPA, or SHA encryption types.
Syringes are commonly used in medical care, such as for intravenous injection in hospitals. Syringes need to be tested and verified before even being used. Some of the tests used to determine the performance of the injector include ANSI, AAMI, ASTM, and ISO. One of the ISO tests includes ISO 11608 which looks at Break Loose, Glide Force, Luer Fitting, Syringe to Hub Retention and Syringe Accuracy. Other testing includes ensuring the biocompatibility of the syringe for when it is inserted into the skin. In addition, there is also transit testing and Package and Sterile Seal Integrity Testing, which deal with the packaging of the syringes. There is also Sterilization Testing, Residual FtO, LP/USP testing, and Siliconization Testing to consider. All these tests are followed for the verification process of syringes by the Eurofins Medical Device Testing.
References:
https://d1jj3zdoktl3jd.cloudfront.net/corporate-eurofins/media/12143127/10006_syringetesting.pdf
A simple example I can think of is a surgical wrench. This device would definitely require a torque test to ensure that it can apply the torque necessary for the procedures it'll be used in. In addition to that, there would most likely need to be a test to verify the length and dimensions of the instrument to ensure that it is long enough to reach where it is needed but not too bulky to fit through. I think would also be beneficial to have a verification test for the force required to use the wrench to ensure that the device can be used with a force that a surgeon would be able to easily apply.
Verification is an important part in developing medical devices or products, and can really help in making sure the products set out to do what they are supposed to. For instance, take tylenol for example; the purpose of tylenol is to reduce pain and fever, but before they sell it to the public, they have to go through a verification protocol to make sure that it does what it says its gonna do. Not only do we check for its effectiveness but its also essential to check for its safety to the people, its biocompatibility, and its effects to the body when ingested. To check these you may have to go through a number of clinical trials, and lab testings to make sure it meets its requirement. All of these factors needs testing which is all part of the verification process.
There are numerous amounts of medical products that require verification testing. Name a medical device or product that exists, and tell us what you think the verification protocol consists of?
Verification activities will be conducted to ensure all design outputs satisfy their design inputs. Design inputs are generally determined based on the type of device, and guidance from the FDA can be taken when creating design docs like a DIOVV.
For a femoral knee implant, some design inputs might be: implant must withstand XX loads of force, implant must translate along the implant construct without creating excessive wear debris, implant must provide sufficient range of motion, etc. So, some verification testing that would be done to test these design inputs would be cyclic load testing, wear testing, and range of motion testing. Acceptance criteria would be defined based on FDA guidance for each of these design inputs, and each test would be done to ensure the device conforms to these requirements.
Verification is a constant process for devices such as computer-assisted surgical systems (CASS). Initially CASSs were approved for use in minimally-invasive surgery such as hysterectomy and prostatectomy. As the market grew for CASSs, the case to use these devices in other types of surgeries also grew. For each additional type of surgery, such as general removal of malignant tissue other than prostates and uteri, an additional verification process was necessary. Each of these processes are considered a separate input because of the varying nature of each type of surgery. Each surgery carries its own risks and must be checked adequately and judged separately to fully understand these risks.
Verification is an important step in Design control. I would like to add some points in the verifications of a DDD mode pacemaker. It is verified using CTTS specifications which determines the voltage and power levels in a pacemaker using UPPAA, which is a standard tool for checking properties of timed systems. UPPAAL can be used to check if a real-time system modeled as a network of timed automata satisfies properties expressed in CTL (Computational Tree Logic). The UPPAAL model corresponding to the CTTS specifications. Further there are additional verifications as well in the verification process.
Design Verification testing for any medical device will demonstrate that the product meets all of the specifications listed out in the DSD/Product Specification document. For a balloon catheter, some of this testing may include testing the force required to pull the balloon out of its packaging, the force required to insert the catheter into a patient, how strong the connections of the catheter are, efficiency of the balloon (how much of its total volume inflates), life testing (how long can it operate at a certain BPM and maintain efficiency and effectivity), and how much force is required to remove it from the patient. In addition to specifying all of the tests that will be done on the device (listing out specifically which ASTMs or company developed test methods that will be used), the design verification protocol will also designate conditioning of samples. Some examples of samples groups include nominal samples (testing performed only after sterilization), transit testing (subject to sterilization then conditioning according to ISO 17025 or equivalent before testing), ageing (subject to sterilization then allowed to sit for the intended shelf life of the device before testing), and sometimes accelerated ageing (subject to sterilization then conditions designed to simulate ageing such as Q-10 ageing).
