We all do protein tests, it’s in the HTM01-05 but which product? Which chemistry does it need to use? Does it need to be incubated? How accurate does it need to be? And where are you meant to use them?
You would think this would be simple to find out – well its not! It requires a bit of digging and some time reading and understanding the HTM01-05, HTM 2030 and ISO standards along with specific product clinical information available from the manufacturers.
Protein Tests -what you need to know
The price and packaging doesn’t matter – that’s preference on your part – what does matter is the understanding of the chemistry, its accuracy and application. Protein tests according to the HTM 01-05 should be performed weekly unless specified otherwise by your manufacturer (HTM01-05 14.3).
Firstly to the chemistry; many tests use the Biuret test method, which is a sensitive chemical test that gives a visible colour reaction when proteins and amino acids are present. The performance of these chemical tests is dependant on time and temperature. The parameters of the specific test you are using must be understood to ensure you are achieving the correct accuracy. For instruments the current published guidance states that an accuracy of less then 5ug per instrument side is required from 15th May 2016. If a Protein test cannot show a theoretical sensitivity through clinical research then it does not meet the standard as it currently exists. Some tests require incubation in order to meet this standard where as others require a longer time at room temperature but not incubation. Each manufacturer can give different instructions so full training should be undertaken before the use of these products to ensure your testing correctly.
Now stay with me…..In order to achieve the correct accuracy, the correct sample needs to be taken. This relies on a sample size and how it is being collected. Protein tests require collection of sufficient testing soil in order to convert the information into a pass or fail result and therefor you must consider how many instruments provide the correct surface area – one? Two? Ten?
This depends on the clinical work done on the protein test itself, upon what parameters does the product work and has clinical evidence to support it claims.
The HTM 2030 states that the limit of detection is 0-2mg protein per square meter and when calculated down to the sensitivity we are talking about the area that needs to be swabbed is a 10cm2. In order to get this size of sample from instruments, six instruments would need to be swabbed in full covering the full surface area. Testing just one instrument would give you a false reading. The way this sample is collected is also important given that a collection using a dry swab picks up considerably less then when using a pre-moistened one.
Finally – Where – One article I found said weekly swabbing one instrument, one weekly on bath / disinfector itself and several other forums and papers giving different versions again.
The HTM 01-05 states that the purpose of the test is to confirm that cleaning has taken place and the process has retained the capability of removing protein. This indicates you are testing the area, which the protein would have originally been i.e the instrument. This is then clarified in its note on page 60 where it states that items should be rinsed with RO water before testing. Testing on 6 instruments should be completed weekly picked at random during re-processing to get a snap shot of cleanliness at this point of the cycle and a full audit kept of the results.
We await publication of the new HTM01-01 standard that is poised to bring further clarity on Residual Protein Tests and potentially change the sensitivity level parameters – for now we wait and see.
Really? I need to know all that?
This is a lot of information to take in, and this is just one product for one validation test from a document that requires several on a weekly, monthly and yearly basis.
What this illustrates is that if we don’t interrogate the tests we are being asked to conduct, the products we need to use and the methods we employ we may be missing the point or wasting our time doing it incorrectly.
These questions and more should be asked, products and processes should be interrogated to make sure you and your team and getting the best out of your test. Regular training and product reviews should take place in practice, engaging with product experts and suppliers where required.
Lets make things clear, remove the mystery and educate on these complex topics.
Hold a practice meeting, make protein tests the topic, and interrogate your product and process.
Originally posted 2016-04-01 09:30:19. Republished by Blog Post Promoter