Laboratory tests: proper communication reduces error

Sanjay A Pai argues that improving communication between clinicians and pathologists is a way to reduce the number of laboratory mistakes

Making a request for an investigation or a range of tests is easy—it is often the easiest thing to do in a clinical diagnostic dilemma. It's the interpretation of the results that may be difficult and may even occasionally lead to a misdiagnosis. This is ironic because the clinician had ordered the test in the first place to help him or her arrive at the correct diagnosis.

For a profession that considers “first, do no harm” as a guiding principle, medicine has had to deal with error. Medical error is a topic that has received considerable attention recently in professional journals, and it has also been highlighted in the media.w1 w2 Much of this has been medication error.w3 Laboratory errors can also contribute to morbidity and mortality. At the very least, they can lead to patient anxiety and dissatisfaction with the laboratory or the hospital system.

Blindly accepting a senseless laboratory value, even if it is repeated and found to be “correct” may be disastrous

You won't go too far by just communicating with your test tube

Definition of error
The definition of error is subjective. Wu et al have defined “medical error” as, “A commission or an omission with potentially negative consequences for the patient that would have been judged wrong by skilled and knowledgeable peers at the time it occurred, regardless of whether there were any negative consequences.”w4 The rate of error varies between laboratories and depends on many factors, not least of which is the competence of the pathologist and technicians. According to Cutler, intralaboratory errors occur at a frequency of 3.65 per 100 tests,w5 while in an extreme case 46% of biochemistry reports in an Australian laboratory were found to contain errors.w6

Types of error
Laboratory mistakes occur mainly at three levels: pre-analytic, analytic and post-analytic. While many clinicians probably believe that most errors in the laboratory are analytic, there are sufficient data to show that the pre-analytic and post-analytic phases are the greatest contributors to laboratory mistakes and form 68-87% of errors.w7 The pathologist often knows the importance of pre-analytic variables, particularly relevant in biochemistry and haematology, but the clinician, the end user, doesn't. Variables such as time of sample collection and length of time of application of a tourniquet can affect haematological and biochemical values. Drug interactions may interfere in various analyses and have been known to confound the best of clinicians. In the era of automation, there are fewer analytic errors. However, in surgical pathology, a subjective field, this is the most common type of error. Post-analytic error may be the result of faulty transcription (the most common problem) or faulty understanding of the laboratory report.

Good communication
Good communication—whether used proactively or in a reactive fashion—is one of the most important means that we have at our disposal in our attempt to reduce error in the laboratory.w8 Proper communication can address all three phases of error. Communication can be initiated from either or both sides—by the pathologists or by the clinicians. The clinicians should know the various tests available in the laboratory and understand their strengths and limitations. Appropriate use of tests is possible only when a clinician is comfortable with the laboratory. In a difficult case, brainstorming through a team approach—comprising the clinician and the pathologist—may produce better results.

Make reports clear
Pathologists must strive to make their reports clear, concise and standardised. A telephone call or a comment in the report to the clinician can avoid many potential problems that may arise from misunderstanding of a concept. Errors in clinician interpretation may be the result of a misunderstanding or unfamiliarity with terminology.w9 It is a fairly common practice in surgical pathology to include a comment in the final report that may clarify a point or increase the doctor's understanding of the report. On the other hand, in biochemistry reports this is not common and, indeed, is not recommended. This is because biochemistry requisition forms often do not contain as much information as histopathology request forms.w10

Unexpected results
It is equally important that clinicians understand the limitations of laboratory techniques and results—as well as ways to reduce those limitations. From the clinician's point of view, it is healthy practice to ask the pathologist to reconsider or re-evaluate a diagnosis when dealing with an unexpected result. Blindly accepting a senseless laboratory value, even if it is repeated and found to be “correct,” may be disastrous. For instance, the presence of heterophilic antibodies can falsely raise beta-HCG levels and lead to a presumed diagnosis of malignant tumour.w11 Again, random errors cannot be predicted. Biochemical or haematological investigations can often be repeated for confirmation of results before assuming that the test is wrong. However, in anatomical pathology, as Murphy states, it may be difficult to reduce a complex issue to right or wrong.w12

Keeping abreast of advances in the field
Hospitals often have doctors from various fields with different levels of understanding and at different levels of training. Furthermore, laboratory science, like other fields of medicine, is growing at a tremendous rate and it is impossible for doctors to keep abreast of all advances in the field. Thus, programmes such as clinicopathological conferences—an excellent forum for communication—or audits and multidisciplinary continuing medical education, contribute vastly to better understanding by clinicians and pathologists of each other's science and, eventually, lead to a reduction in error.

Sanjay A Pai, consultant pathologist, Manipal Hospital, Bangalore, India
Email: bS_pai@vsnl.com

I thank Dr Satish Amarnath for his comments. 

studentBMJ 2005;13:397- 440 November ISSN 0966-6494

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