Negative Test Results

A wise old doctor once told me that there was no such thing as a negative test result.  At the time I didn’t quite understand the significance but I have since come to strongly agree.

Much of the contemporary evidence on psychosocial aspects of pain management and clinical guidelines for interventions in low back pain in primary care discuss the relevance of supplementary investigations. In musculoskeletal practise we are generally concerned about imaging, bloods and differential diagnosis. From the clinicians perspective the primary reason for requesting investigations is to assist with diagnosis and exclude “Red Flag” pathology.  What has come to is the routine request of a battery of investigations without linking the necessity of investigations to the clinical findings. This lazy approach is sometimes referred to as “defensive Medicine” and is driven by a desire to avoid mal-practise suits or is part of the personal injuries litigation process. This has subsequently increased patient’s expectation that investigations should be routinely conducted. Unfortunately there is frequently an erroneous belief that these tests will actually change management – the fundamental reason for any supplementary investigation.

We know as clinicians that any investigation should be done for the purposes of influencing/directing management.  This issue is clouded by the complexity of the clinical reasoning process and the reality that there is not 100% correlation between clinical findings and pathology.  This can work in two ways.  Firstly, that the clinician’s perception raises suspicion of serious pathology or alternatively relatively modest clinical signs in the presence of serious pathology.  The question is whether we leave decision making to clinical judgement or pursue a course of routine implementation of tests as advised in “Guidelines”.

With the advent of psychosocial profiling the role of supplemental clinical tests came more in focus. This was because of the observation that some patients “ believed” they have serious pathology which might be demonstrable on investigation and unless tests are conducted an element of doubt persists, preventing progress beyond a rehabilitation roadblock.  Therefore just because a guideline says that routine x-ray is not appropriate from a clinical perspective if a patient perceives that it is of particular relevance then it will be hard to convenience them otherwise and thus pose a barrier to progression. As clinicians we may feel content in the security that guidelines provide – allowing us adopt a certain position to guide the patient /therapist discussion. However, we need to ensure we bring the patient along and this cannot always be done with discussion alone in my experience.

This does of course raise the issue of cost and who underwrites expense associated with what might be perceived as clinically spurious tests. I would argue nonetheless they are relevant / useful if the patient perceives them to be provided they can be used as a springboard to lever beyond a clinical bottleneck.

I find it useful to manage these patients who have a need for supplementary tests in the absence of clinical signs by attempting to predict what the scan, x-ray or blood test is likely to show.  This of course does put the clinicians ‘head on the block’ but it does establish confidence and enhance the credibility of the clinician (provided the results were correctly predicted).  And what if I predict wrongly I hear you say?. The answer is that there is always a cohort of patients where the clinical signs don’t match the pathology and even this can become a positive by establishing a baseline or allowing the clinician to outline what the particular symptom characteristics are associated with degeneration, spondylosis, inflammation, osteophytes etc to “match” or refute the patients symptoms.

One significant barrier can be the delay in pursuing adjunctive tests particularly if this is through a public health system and this often becomes an impediment to committing to rehabilitation pending the outcome of the tests.  Sometimes patients perceive a negative test as a lack of vindication of the existence of their symptoms and often appear to be somewhat disappointed.  From a therapeutic perspective the tables can be turned to use this evidence in a positive way to deconstruct any distorted perceptions of imminent structural failure and coax the patient into a progressive rehabilitation regime.  So on this basis I think we can say there is no such thing as a negative test – it just depends on who’s perspective.

Enjoy the clinical challenge.

David.

GHTime Code(s): d96dd 

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