8 replies to this topic

[Lucas]

Hello all,

This is the first time I am posting on this site, which I consider to be a wonderful place where inteligent people can chat about Quality and Safety issues and/or doubts.

BRC issue 5, clause no. 5.5.2.4 states that shall be procedures in place to ensure reliability of lab results, making use of ring or proficiency trials to verify the their accuracy.

However, and in spite of I had already worked with these before, what do you think are the biggest differences between ring and proficiency trials? How can we differenciate them?

What is the best way to check the accuracy of a determined lab?

I would like to have your input on this.

Many thanks,
Lucas

[Simon]

This is the first time I am posting on this site, which I consider to be a wonderful place where inteligent people can chat about Quality and Safety issues and/or doubts.

Hi Lucas, welcome to the forums. With that kind of opening compliment I'm kind of surprised nobody has answered your query.

Can anybody help Lucas on this?

[Charles.C]

Dear Lucas,

This ring / proficiency idea looks like another one of the brc “innovations” as previous versions were far less precise from memory.
I hv always periodically submitted an “in-house reference” sample to a few ISO 17025 accredited labs and compared the results to own lab for self protection rather than for brc, this is a very small, ad-hoc version of the real thing of course but seemed to satisfy the brc auditors, probably because they didn’t understand the micro. results (a very non-exact science) anyway. In other non-food applications where large contracts are involved, reference labs are often nominated in case of ajudication and I usually tested such labs for bias by similar methods although with a bit more statistics thrown in since more ‘accurate” data available.

Was a bit unclear of the terminology(s) here but after a bit of googling, seems that ring testing is just one of the methods within the general assessment of lab “proficiency” rather than 2 separate, specific tests as I initially inferred from yr post ?? eg –

This paper illustrates that proficiency testing by ring trials is a method of comparing panel performance. It highlights the fact that even highly trained panels, familiar with the product, can be subject to the occasional inconsistency, relative to other panels. However, this should be viewed in the context of the overall sensory test.

http://www.sciencedi...ad80b112a678f5d

If this is correct, not quite sure to which comparison yr query is referring, another particular type of proficiency test ?? I hv equally possibly misunderstood the post in which case perhaps you (anybody) could correct / elaborate a little. Interesting topic which deserves to generate some comments.

Rgds / Charles.C

[Lucas]

Hello again,

Perhaps I didn't make myself that clear.

My question was about if there is any difference what is called "Ring Trials" and what is called "Proficiency Tests".

I worked for a company in England that used to make these tests. I am not sure now if they were the same thing (but with different names) or if they had in fact some differences. What I do remember is that our lab used to, periodically, prepare an inoculate and send them to our supplier labs to test. Our internal lab would then analyse the results and produce a table with a statistical analysis saying exactly what were the labs performance. We could see easily what were the labs with poorer performances, which could help us in our periodic audits.

I do not know what kind of inoculate our internal lab used, as that was there responsibility.

When I was reading BRC issue 5 I bumped into ring/proficiency tests again and my thoughts started to pop into my head.

So, in summary, my two questions are:
- Are there any differences between Ring Trials and Proficiency Tests? Or they are the same thing?
- Although the lab I use now is ISO 17025 certified, is that enough to answer to clause no. 5.5.2.4 of BRC issue 5?

I hope anyone can help.

Thanks once more.
Lucas

[Simon]

So, in summary, my two questions are:
- Are there any differences between Ring Trials and Proficiency Tests? Or they are the same thing?
- Although the lab I use now is ISO 17025 certified, is that enough to answer to clause no. 5.5.2.4 of BRC issue 5?

Just looking back at open topics from the past couple of weeks and noticed this outstanding. Can anybody please help Lucas with either of his questions?

[Dr Bob]

Hi,

Sorry I haven't got a copy of the standard infront of me (it is Sunday) so please bear with me.

The accuracy and precision of methods can be assessed using protocols in ISO 5725. This involves analysis of several samples by multiple laboratories and using stats to get the figures. CCFRA publish a document specifically for micro methods.

BRC require that we assess the ongoing accuracy of the site laboratory.

Issue 5 requires we operate to the principles of ISO14025. This standard says that a laboratory should test the accuracy of testing by participation in an accredited scheme where such a scheme exists. I would class such schemes as 'ring testing' ie several labs testing an unknown sample and reporting results back to an independent organisation that collates and statistically analyses the results. Some schemes use 'expert' labs to provided the 'real result'.

Such schemes can now be certified by UKAS or country equivalents. I'm not sure of the standard (may be PD 6644-1:1999, ISO/IEC Guide 43-1:1997 Proficiency testing by interlaboratory comparisons).

Check out the LGC (http://www.lgcpt.com/schemes.aspx) or Bipea (http://www.bipea.org/).

Obviously if a scheme does not exist, the scheme you described - where a central function performs the 'ring testing' is acceptable (providing auditable and defendable).

Where ring testing is not available you must assess performance by other means. This I would class as 'proficiency testing' in a general sense. It is best practice to do this to back up the ring testing. I would include:

Analysis of internal quality assurance samples eg unknown reference samples or 'spiked' samples (ideally anaysed by an 'expert' certified lab).
Analysis of a sample followed by analysis of an expert laboratory
Analysis of known certified materials

To demonstrate compliance to an auditor I would place in order:

Use of a certified proficiency scheme (ring testing)
Use of an independent non certified scheme (ring testing)
Use of a central function scheme (ring testing)

Supported by other means of proficiency testing:
Analysis of internal quality assurance samples
Analysis of a sample followed by analysis of an expert laboratory
Analysis of known certified materials

Micro schemes are always fun - depends to a great extent on how representative the sample is.

I'm afraid that whatever my views, it always comes down to the auditor on the day as to what he thinks is acceptable.

All I can say is that it got me through my Issue 5 audit!!

To sum up I'd say ring tests are one of the options available as part of proficiency testing.

Hope it helps

Rob

[Simon]

Great first post Dr. Bob, thanks for your contribution. I hope Lucas is still around to see it.



Regards,
Simon

[Lucas]

Hello,

Your post was of great help, Rob. Thanks a lot. You were very clear.

Unfortunately, on our last meeting with our biggest client they pushed us to change the certification referential to IFS.

I am going to buy it and start reading it as soon as possible, as I don't have any experience with IFS.

It shouldn't be much different from BRC, I suppose. I am not too worried (yet!), as I am counting on my experience with ISO 22000 and BRC to help me a bit. And then, I can always look up on this fabulous site for some help.

Thanks a lot for your enthusiastic help, Rob.

I promisse to participate and post with more frequency.

Simon, you were excellent. I was getting abnegated to the idea that I wouln'd be answered as clear I was.

Thanks once more.

Regards,
Lucas

[cazyncymru]

Hello,

Your post was of great help, Rob. Thanks a lot. You were very clear.

Unfortunately, on our last meeting with our biggest client they pushed us to change the certification referential to IFS.

I am going to buy it and start reading it as soon as possible, as I don't have any experience with IFS.

It shouldn't be much different from BRC, I suppose. I am not too worried (yet!), as I am counting on my experience with ISO 22000 and BRC to help me a bit. And then, I can always look up on this fabulous site for some help.

Thanks a lot for your enthusiastic help, Rob.

I promisse to participate and post with more frequency.

Simon, you were excellent. I was getting abnegated to the idea that I wouln'd be answered as clear I was.

Thanks once more.

Regards,
Lucas

I did my dissertation on Proficiency testing, just to see if they were value for money.

In my experiences, a sample is sent out, and you could grow it on any media you so required!
i took yeast and moulds, and grew them on a variety of media, from Rose Bengal, Y & M agar, Potato Dextrose, Malt , OYGE, Petrifilm and (disappointingly) they all came back fairly close to the standard value.

So it demonstrated that
a) im damn good at getting repeatable results (all tests done in duplicate)
b) that a proficiency scheme is (saddly) worth the money.

We also do ring trials, where a sample is given to all and sundry in the lab, to see how repeatable the test is. a subsequent sample is also sent to our external lab to verify the results.

Currently we do all our microtesting with an external lab, but i have just had the funding to bring this all back inhouse, so i can have more control on what results we are getting.

Caz x