I'm enjoying this discussion. Here are my seven - done over the weekend. The original ones were great but IMVVHO could have been put more succinctly. I've got space for three more, Steve!
1. Thou shalt remember that all tests can do harm, many tests do good, some tests do more good than harm, and that the test result giveth thee only a probability, not a certainty.
2. Thou shalt not worship sensitivities and specificities, regardless of how near they are to 100%, for without knowing the person's pre-test probability, they shall give thee no help.
3. Thou shalt know the positive and negative predictive values of the test before thou ordereth it, for if the one thou art interesteth in art less than 50% verily thou shalt be better off tossing a coin
4. Thou shalt consider a test only if the result will affect thy management plan and not just because thou always doeth it
5. Thou shalt know the cost of the test before thou ordereth it, and whether there are cheaper ways of finding the same result.
6. Thou shalt share decisions with the patient about what tests to do, including the predictive values and the implications of the possible results or even having the test done at all
7. Thou shalt record the result of the test very clearly for all that come after thee to see, for verily if anyone repeateth it without good reason they are wasting resources.
Andy Hutchinson MEd, PHARMACIST
Education and Development Manager
National Prescribing Centre
Provided by the National Institute for Health and Clinical Excellence
Ground Floor Building 2000 | Vortex Court | Enterprise Way | Wavertree Technology Park | Liverpool L13 1FB
Tel: 07824 604962
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-----Original Message-----
From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Steve Simon, P.Mean Consulting
Sent: 09 January 2012 16:31
To: [log in to unmask]
Subject: Re: Ten commandments for testing
There are a few important aspects of testing that are missing here. Or maybe they are there, but are not explicit enough. Or maybe I'm the one missing the point. But anyway, here are some of my thoughts about the list.
First, there is always the temptation to please the patient who thinks that more tests equals better medical treatment.
11. Thou shalt not order a test just to placate thy patient.
Second, there is a financial conflict of interest when a doctor buys expensive new machinery.
12. Thou shalt not order a test just to help make payments on thy new diagnostic equipment.
Third, there is a tendency to notice the one spectacular failure and give it disproportionate influence.
13. Thou shalt not let a single anecdote dominate thy thinking.
Fourth, there's a tendency to slavishly follow previous practices.
14. Thou shalt not order a test just because that's always what's been done in the past.
You need, of course, to keep this at ten commandments. You might combine
#4 with #5 or with #6. Or you could incorporate #11 with one of these.
You could also combine #12 with #3 or #8. #13 is probably just an additional elaboration on #10. #14 might fit in with #9.
Also, the concept of predictive value in #1 is a bit muddled. It's perfectly fine to accept a PPV of 10% in a setting where additional follow-up is cheap and the consequences of false negative is extremely severe. The classic example is diagnosing cervical fractures in the ER.
There is a cost to unnecessary x-rays, but it is still relatively small when compared to sending someone home with an undiagnosed problem. These people come back three days later in a wheelchair and with a team of lawyers accompanying them.
Good luck. When you finalize this list, please make sure it gets published someplace prominent.
Steve Simon, [log in to unmask], Standard Disclaimer.
Sign up for the Monthly Mean, the newsletter that dares to call itself average at www.pmean.com/news
On 1/7/2012 9:40 PM, Michael Power wrote:
> Thou shalt obey the following ten Commandments for testing, whether it
> be for ruling in a diagnosis, ruling out a diagnosis, assessing risk
> or prognosis or response to treatment, or for monitoring for adverse
> effects and deteriorating status.
>
>
> Thou shalt understand testing in its broadest sense; it includes
> history, examination, laboratory tests, imaging investigations,
> diagnostic procedures, and therapeutic trials.
>
>
> When a commandment is impractical or impossible, thou shalt treat it
> as an aspiration and do thy best.
>
>
> For I am thy patient and client, whose interest thou shalt serve, and
> no other.
>
> 1.*Evidence.* Thou shalt not take the evidence in vain, but test
> according to the best estimates of prevalence, positive predictive
> value, and negative predictive value. If the predictive value of a
> test is less than about 50%, toss a coin - it will be cheaper and as useful.
>
> 2.*Application of evidence. *Thou shalt not overly rely on test
> results, but shalt apply your clinical judgement after clinically
> assessing your patient and critically appraising the evidence, taking
> into account its precision, risk of bias, and directness of applicability.
>
> 3.*Cost-effectiveness.* Thou shalt not covet thy neighbour's graven
> image technology (PET scanner, fMRI scanner, high resolution
> ultrasound scanner), nor his micro-array genetic tests, nor his direct
> to consumer testing business, nor his yacht, nor any thing that is thy
> neighbour's, but thou shalt practice cost-effective testing. If a
> cheaper test will be as useful, use it.
>
> 4.*Patient-education.* Thou shalt help thy patient understand that
> many diseases are gradual and progressive, analogue processes not
> digital events. Diagnostic thresholds and limits are chosen for
> convenience, but create artificial categories that may be misleading
> if they are misunderstood as boundaries between having and not having
> a disease, or having and not having a risk.
>
> 5.*Joint decision-making.* Thou shalt help thy patient understand the
> limitations of tests. Many conditions cannot be diagnosed or excluded
> by tests (for example dementia, wellness). Tests can be falsely
> positive or falsely negative or inconclusive. No test can give a
> precise prognosis for survival or other probability, and
> interpretation of prognostic tests should consider both the average
> (median or mean) and the distribution in the comparator population.
> Thou shalt remember that test results can in themselves be distressing
> or harmful. For these reasons, decisions about testing are best made jointly with thy patient.
>
> 6.*Patient-centred care.* Thou shalt not take thy patient's needs in
> vain, but before testing help them understand what the management
> options are for a positive, inconclusive, or negative result, and what
> support is available should the result be distressing. Honour the
> elderly patient, for although this is where the greatest levels of
> risk and temptation to test reside, so do the greatest needs for
> avoidance of useless and harmful testing.
>
> 7.*Efficiency.* Thou shalt not repeat a test when the result is
> already available or the result will not change (as with genetic tests
> or when the clinical indications have not changed). Thou shalt ensure
> that the results of tests you have ordered or performed are clearly
> recorded and available or communicated to any other physician caring for thy patient.
>
> 8.*Ethics.* Thou shalt not use testing as a defence against legal
> action, or as a placebo, or as a delaying tactic while nature takes
> its course, or to avoid confronting the limitations of curative
> medicine when care, support, or palliation is appropriate.
>
> 9.*Education and engagement.* Thou shalt help thy trainees and junior
> colleagues understand that they should investigate having considered
> the needs of their patients and the performance of the tests. The
> reason for testing should not be that it is routine, or policy, or
> what they imagine their consultant/attending expects.
>
> 10.*Gnothi seauton. *Thou shalt know thy cognitive limitations. Thou
> shalt try to avoid the fallacies of assuming that all abnormal results
> are important or that an abnormal result is sufficient to explain
> symptoms. Thou shalt consider the whole picture, and the differential
> diagnosis, and the possibility that tests bear false witness.
>
>
>
>
>
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