‘I’m fishing really’ — inflammatory marker testing in primary care: a qualitative study

Abstract

BackgroundInflammatory markers can be helpful as part of the diagnostic workup for specific diseases or for monitoring disease activity. A third use is as a screening and/or triage tool to differentiate between the presence or absence of disease. Most research into inflammatory markers looks at diagnosis of specific diseases and comes from secondary care. Qualitative studies to explore when and why clinicians use these tests in primary care are lacking.AimTo identify clinicians’ approaches to inflammatory marker testing in primary care.Design and settingQualitative study with 26 GPs and nurse practitioners.MethodInterviews were conducted using a semi-structured topic guide. Clinicians reviewed recent cases of inflammatory marker testing in their pathology inbox. Interviews were audiorecorded and transcribed. Qualitative analysis was conducted by two of the authors.ResultsClinicians are uncertain about the appropriate use of inflammatory markers and differ in their approach to testing patients with undifferentiated symptoms. Normal or significantly elevated inflammatory markers are seen as helpful, but mildly raised inflammatory markers in the context of non-specific symptoms are difficult to interpret. Clinicians describe a tension between not wanting to ‘miss anything’ and, on the other hand, being wary of picking up borderline abnormalities that can lead to cascades of further tests. Diagnostic uncertainty is a common reason for inflammatory marker testing, with the aim to reassure; however, paradoxically, inconclusive results can generate a cycle of uncertainty and anxiety.ConclusionFurther research is needed to define when inflammatory marker testing is useful in primary care and how to interpret results.

C-reactive protein and neutrophil count laboratory test requests from primary care: what is the demand and would substitution by point-of-care technology be viable?

“…Unlike for the NC, we observed that the proportion of patients who underwent a CRP test increased from younger to older age groups. Diagnosis in the older age groups may be more difficult because of non-specific presentations (such as absence of fever with infection)33 and GPs may be using CRP in addition to the NC to screen for serious illness 9. Potentially, the availability of portable CRP devices may be very beneficial in assisting the diagnosis in older frail or housebound patients for whom access to blood tests is more challenging.…”

Use of tests in UK primary care

“…A systematic review and meta-analysis of 14 randomised controlled trials investigating the effect of diagnostic tests for patients with a low pretest probability of serious illness (presenting with symptoms such as fatigue and low back pain) reported that testing did little to reassure patients, decrease their anxiety, or resolve their symptoms, although tests did reduce further visits to primary care 10. Qualitative research highlights diagnostic uncertainty in relation to non-specific symptoms as a common reason for inflammatory marker testing, with the aim to reassure 11. However, inconclusive results can paradoxically generate a cycle of uncertainty and anxiety 1112…”

“…Qualitative research highlights diagnostic uncertainty in relation to non-specific symptoms as a common reason for inflammatory marker testing, with the aim to reassure 11. However, inconclusive results can paradoxically generate a cycle of uncertainty and anxiety 1112…”

Viewpoint: Doing nothing

“…4 All of this can contribute to our everspiralling workloads, as Des Spence has recently highlighted. 7 Another GP we interviewed described the impact:…”

“…Unfortunately this can lead to a vicious cycle; rather than reassuring ourselves, inconclusive or borderline results can generate increased uncertainty and anxiety. 4 This in turn can lead to cascades of further tests, in what has been termed 'investigation momentum': the relentless pursuit to resolve uncertainty. 5 Testing to 'reassure patients'.…”