More Rejection.

Sometimes rejection is a good thing, at least when thinking about laboratories protecting the quality of their work and output.  Rejection criteria are created to protect the laboratory, the clinician and the patient.    The laboratory protects itself from doing needless work and work with little chance of clinical utility.  The clinician is protected from receiving information that might be non-contributory, or worse, might lead to wrong decision making.  The patient is protected from spending money for additional tests and therapies that would not have been ordered had things been done right the first time.

In a litigious society working on poor quality samples has a higher probability of costing the laboratory more through legal fees than than it recovers in test revenues.


In the non-litigious society, reporting results that are either clinically-irrelevant  or clinically inappropriate damages the laboratory’s credibility.  Frequently we hear in laboratories in developing countries that the reason that so few samples are sent to medical laboratories is because the doctors don’t trust the results.  By tightening up on the quality of samples that are accepted for testing results in increased confidence in the results and increased samples being processed.  


But as with most things in life, rejection criteria are not a “one-size-fits-all” decision process.  I can give you a few examples as they appear in the microbiology laboratory.  

The first example is one where the sample is accepted, but the request is rejected.  Frequently we receive urine culture samples submitted with a requisition that says “test all organisms for antibiotic sensitivity” or “test all organisms for urease activity”.   Usually these requests are motivated chronic recurrent symptoms of infection or stone formation.  Well that sounds good and the information may be useful if the samples are pure (one isolate) or near pure (2 or 3 isolates).   But there is no value in testing every isolate in a polymicrobic sample with 4, 5 or 6 different isolates.  There is no reason to do high level testing that you know will not contribute relevant or useful information.  

There are many ways of dealing with this sort of rejection, and usually it requres having a conversation with the ordering clinician, but sometimes the clinician has to understand that extra testing is not going to get done.

Another example is what might be called  cascade rejection.  This is where the sample comes with a request for all isolates to be tested for susceptibility to satifloxacin. This is a situation where as soon as the “new drug” shows up in literature, requests for testing show up in the laboratory.  This is where antibiotic stewartship needs to kick in.  If the drug is not on the facility formulary list or the current laboratory list, it is not going to get tested, unless there is a research protocol to which the laboratory has agreed to participate,  and this information is not going to be available for random and regular use. 



Two last quick thoughts.  


First,  Most laboratories do not have the computer power to build rejection criteria into the laboratory sortware, which will be terrific when it happens.  When that happens all sorts of complex “if...then” layers can be implemented, and the system will label the sample and block steps all along the sample’s path of workflow.  Until that time comes, the application of rejection criteria falls to the memory of frontline workers with lots of work pressures. Creating straightforward criteria have a reasonable chance of being implemented.  Complex criteria are have little chance for success unless senior leaders personally insert themselves into the intervening process.  


The second quick thought is that proficiency testing programs can and should  provide programs to challenge rejection criteria.  More on this later.

Not all rejection is bad

In a recent proficiency testing sample for parasitology we submitted a sample with known artifact from poor handling (freezing).  I can’t say we sent this one totally on purpose, but we have in the past sent samples clearly designed and intended to challenge the laboratories’ rejection criteria.  What we observed was that less than 5% of the laboratories included a cautionary note about the quality of the sample.  
What I would have anticipated was that a substantial number of reports should have come back containing a cautionary note to the effect: “Caution: sample demonstrates artifacts suggestive of improper collection or handling.  Please submit an alternate sample”.

Proficiency Testing is supposed to challenge normal sample handling.  We hope that what we have seen is a failure of laboratories to handle this sample like a normal sample, rather than suggesting that  more than 95% of laboratories would generate a report without commenting on suboptimal quality of the sample.   

Laboratories know all too well that a number of samples reach the laboratory in an unacceptable condition.  They may have been collected incorrectly, or perhaps put into the wrong container with the wrong fixative or anti-coagulant.  They may have been collected properly, but not labeled in a way that anyone could say with any confidence from which patient they came.  Or they may have been collected properly, and labeled properly, but transported in a way that would not protect the sample from complete or near complete decay.  Unfortunately for all those reasons, the samples all fall into the same category: junk samples.

Working on junk samples is not only counter productive, it is dangerous because  reports virtually never include the cautionary statement “please note that this result has little chance of being accurate or relevant due to the poor quality of the sample.”  

ISO15189:2007 includes the requirement for sample Rejection Criteria (see requirement 5.4.8).  Laboratories have an obligation to establish the requirements of a sample, and to reject samples that don’t meet the requirements.  It is for the good of the patient, and for the good of the clinician to avoid making decisions based upon faulty information from faulty specimens.  

And we believe that PT programs have an obligation to intermittently challenge the laboratories’ decision making.  Is there any difference between demonstrating that a laboratory tested a good sample and got a wrong answer or demonstrating that a laboratory tested a poor sample and got a poor answer?  Well there is a difference, but the bottom line is the same.  The clinician receives a report with information potentially damaging to patient care.

At this point, let me point out that even the international standard misses an important consideration of sample rejection.  Not all sample rejection is the same.  There are different levels of rejection, all of which are acceptable, appropriate and to be expected in their respective situations.  And proficiency testing schemes are ideally placed to challenge all these level.

More on this later.
M


PS: For those that want or need more information on the international standard, see: The ISO 15189:essentials - A practical handbook for implementing the ISO15189:2007 standard for medical laboratories.  November 2010.  CSA Standards.
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