I would like to have an opinion regarding the test/calibration of test equipment that are used in preventive maintenance of medical equipment.
Let's say for example I am doing PPM on a patient monitor. A suggestion of our ISO consultant is that instead of sending test equipment yearly for calibration, we should set aside a "reference monitor" as the basis for calibration.This reference monitor will be unused say for 3 years.
Logically there is a sense to this idea but I am not very comfortable with it.
My question is-if an equipment is unused(i.e. kept in the cabinet) would it be right to assume that the calibration can be extended to more than 1 year? Also can said equipment be used for reference?

My experience with using 'secondary standards' as calibrated references is that you must prove them first. That is you need to select several items and repeatably check them over a period of time and select the one with the best stability. you then need to back this one piece of equipment up with another stable reference to be used when you suspect that the first of giving an unexpected result. Even then you can not be absoluteley sure of your calibration. I would only normally recommend doing this when direct calibration against standards is not possible.

Strange, our consultant said that we should not use non certified equipment for "Calibration", however we can use some other types of equipment for Go/No Go type checks or for general indication.

We do use some devices for "indication / reference only" that we could check against one of our calibrated devices.

As an example, we do have some calibrated multimeters, however the majority are for reference only (to save costs).

I would discourage against general non-calibration of test equipment, particularly if you are calibrating against it, however sense and logic allows you to single out individual devices that may be markered as "reference only".

Regards
Joe

IS it then a strict rule that test equipment used for calibration should be factory calibrated yearly?
Of course there are ways of calibrating it ourselves but then there is again an issue of "traceability". The standards that we will be using are subject to calibration too.

Yep, during quality audits of our dept, the assessor will pick up pick up various pieces of test equipment, if not marked as reference only she will request the paperwork to show that it has been calibrated to national standards.

It has been quite a flesh giver over the past couple of years, but finally we can put it to bed as it is all fully documented now. Once they know you have corrected your ways they wont ask so often.

.... but whats next

If you want to calibrate test equipment (like multimeters) you can buy a calibration standard (which you must then have calibrated regularly) and check all your meters against it.

Unless you've got a lot of meters it's cheaper to just send them off to a local calibration lab !

As for checking the calibration of medical equipment, I wouldn't trust a piece of equipment which had been sat in a cupboard for a couple of years to be an accurate "standard" to do comparrisons against. That also sounds like a very expensive way of achieving the desired result - or not, as the case may be !

Just thought i would revive, and slightly extend this topic.

As the general consensus appears to be that we do send test equipment away for calibration, and require the provision of the all important certificates traceable to "national standards" (obviously only talking about the UK here, so how this issue is dealt with in the majority of the world would also be interesting to hear).

Which companies do you all find provide an efficient / reliable and of course "competetively priced" service.

Hopefully, we might learn about some gems out there that could save us all money!

The general consensus amongst those funded by the taxpayer, perhaps?

Those who dwell in the Real World have to minimise expenses by, for example, applying a bit of what we might call nous.

For example:- although we know that it's working just fine, and even suspect that it's well within spec, test equipment item No.1 gets sent away to gain its (expensive) seal of approval.

When at long last we see it again (after being bounced - and, most likely, chucked and kicked - about in various vans), we assume that it's now "perfect", especially as it now carries that all-important feature ... a piece of paper.

But (cunning folk that we are), we now compare (and, if necessary - but it seemingly never is - re-calibrate ... as in "adjust") test equipment No.2 ... No.100 against No.1. Traceable to "national standards"? Yes, why not (just as long as it's documented ... as in "noted, signed and dated in the test equipment log book")?

You are fishing for gems? OK, here's the first one:- you just need to be thoughtful about which bits of test kit you select for "sending away". Send the one(s) with "all the features". Whilst also bearing in mind that some things matter more than others. For instance, what sort of tolerance is good enough on a multi-meter? Or, for that matter an electrical safety tester?

And here's another:- check all your test kit yourself, then only send away the ones that fail that most stringent of the Laws of Physics. You know, the one attributed (quite rightly) to Herr Georg Ohm.

Joe has already mentioned "Indication - for Reference Only", but I would extend this even further by suggesting that such instruments (if you know them, and feel confident about using them) are entirely adequate for the vast amount of testing (checking, fault finding) work carried out in the workshop.

So there's the final "gem":- get some suitable stickers made!

Unless, of course, you work for the NHS ... when you might as well send away the whole lot, and then let them sit prettily on the shelf for yet another year!

Are you sure - or is it a case of maximising profit....

Come Geoff give the NHS workers a day off from your vitriol. This is a valid question about people trying to do the right thing.
My world is real - trust me!

Yes, it's a valid enough question.

So where are the (your) valid answers?

No so long ago, for us to service PCT equipment required us to have in place an approved ISO system. This was true of private contractors as well as NHS EBME departments. the PCT was then satified that we were woking to a set of standards.We were advised on the contents of our ISO documentation by a consultant who is an expert in these matters. He recommended that it is only necessary to have one of each item calibrated to National Standards and this item must be used when calibrating medical equipment. Other test equipment can continue to used, but not for calibration.

Like John, I notice that Geoff tries his best to give honest NHS workers a bad time. All we do is to maintain a quality standard that has been legislated by the government.

From Part 1 of your post we seem to be in broad agreement there, Graham.

Not so sure about Part 2, though.

I always like to give everyone a fair go, Mate ... and you have been kind to me in the past. But three points if I may:-

1) Any comments I may record vis-à-vis practices in the NHS (nota bene not the "workers" themselves) are based on my personal observations over recent years (not to mention over 35 years of involvement with "practices" elsewhere spanning from "Best" to ... er, "Worst")!

2) Remember (as I never tire of mentioning) there is a Whole World of Biomed outside the British government health services. Many techs come here (on the forum) looking for clues, tip and advise in general ... and probably don't know anything (or couldn't care less) about the NHS.

3) Yes, I acknowledge the "guidelines" spewed out by government. But as far as I am aware, it is not always "legislation". Some of what goes on is (IMHO) only done for, shall we say, traditional (and/or CYA) reasons.

Over the pond here in Canada test equipment must be sent once per year for cal and testing by labs that have the NIST designation. www.nist.gov/index.html.
I do not like the idea of a reference unit being held in a closet. My experience has been that cals can and will drift even if the unit is not being used.
It depends on the piece of equipment. A hemodialysis machine for example would definately drift.

Does NIST exist in the UK? If not is there a similar type organization?

I don't think that is very fair, Geoff gives everyone a bad time not just the NHS folk

Now, back to the matter at hand.

Calibration of all test equipment is essential and, in this part of the world anyway, it is required that the test/cal be done by a certified testing agency (in Oz that NATA certified). The one thing that can however be varied is the frequency of that calibration. Once again however, this comes back to our old friend, a "risk based approach".
As an example of this a maker of electrical safety testers here (MEM) recently changed their recommendation from yearly to two yearly as it was found that this was quite sufficient and did not affect the reliability of the testing done.

Yes, although Bong's original post was headed up "Test Equipment Calibration", he then went on to talk about Patient Monitors in cupboards. Which is not a good idea.

I have given a "dissertation" about the calibration of test kit before (but lack the time, and frankly the inclination, to look it up again now). In short, if you're not careful, it ends up being yet another money making opportunity - for the calibration lab, that is - "calibrating" thousands of items every year which weren't "out of cal" in the first place. Then shipping them back to you (how? when?) in possibly a worse "state of cal" than they were in when you sent them off!

As I have said before, be thoughtful about what you send away, then refer other items (of test equipment) to the ones that have been "certified".

If you use your test kit often and regularly (and don't have too much of it - enough is enough) you will get to know which ones you can trust, and depend upon (hopefully, all of it). Once again, Rocket Science it ain't!

Hi Rug, the standards are maintained by the National Physical Laboratory (NPL), and organisations that test to these standards are accredited by UKAS.

My understanding from the comments here then is that some of us have the freedom to use a risk based/common sense approach, others have to provide the all important "piece of paper".

What we have in common is that everyone, at some time, has to send one or more pieces of kit away to be calibrated.

The "gems" i was looking for in my first post were those companies that we have found and prefer to use, and the reason why...... whichever part of the world we live in.... hopefully many of us may save some money in this way.

So, as a starter.. Having just had need to find a calibration agent for half a dozen items, my nomination would go to ServiceCal in Manchester.

Jolly good. Care to share with us ... why that is so?

Meanwhile ... let's have some more nominations (from others). I have found in the past that cal labs "come and go", as it were. Our lists need updating.

And ... who does what! What about my old RT-200, for instance? And who does the Datrend Infutest, and the IDA series of pump testers? What about the Bender 601 safety tester (yes, the list is seemingly endless).

Does anyone get ECG simulators calibrated? Where (and why)?

Also ... I would phrase the thing somewhat differently:-

Some of us have the freedom to use a risk based/common sense approach ... backed up by appropriate "pieces of paper"!

When you go down the road of accreditation, then everything will have 'a piece of paper' if an accident/incident occurs then the paper chase will begin to find the cause. If your paperwork is all in order then nothing to worry about.

The risk based approach is probably the best system - with 1 caveat - you have enough evidence to back up your final calibration schedule.

As long as nothing goes wrong it will never be questioned, but if an unfortunate incident does occur, you would be hard pushed explain why you changed the calibration frequency from the manufacturers recommendations without this evidence.

Lets face it, the only reason most things are checked annually is because it is easier to manage.But in this silicon era, we let computers do the hard work for us....

With reference to the calibration of ecg simulators, they should be calibrated. Why - check this link out :
http://www.anaesthetist.com/icu/organs/heart/ecg/Findex.htm

If you do not know what signal you are putting in, how do you know you are getting the correct signal out!

We use 3 main suppliers being
Utramedic.
CalCom.
&
Gauges North West Ltd.
All 3 provide an excellent service for the kit we send them.
The later will do the RT200 and issue a cert.
Apart from the previous discussions above I've also found that a lot of OEM courses state that you use a calibrated tester somewhere in the service / repair procedures. If you dont know the tester is within cal how can you set anything on the kit you are calibrating.
Then again the british standard calibrated thumb for presuures and temp is a good alternative. The ear version being useful for breathe rates and flow patterns.

I would have thought that a "calibrated" BPM over a span of settings is all that is required for an ECG simulator. And that is something that can be done "in-house" by checking against some other piece of Certified kit, like an oscilloscope.

In my experience the content (shape etc.) of the waveform(s) vary somewhat (and sometimes by quite a noticeable margin) ... so unless there is some "British Standard Sinus Rhythm" (and then all the arrhythmias) then I guess we need to settle for what the *Bio-Teks of this world dish up.

* Other manufacturers of ECG simulators may be available.

We bought a calibration 'stick' for all the hight measures in the trust. I don't think we have ever sent it away for calibration. Do you think we should?

Just use your yardstick ... as the er, yardstick!