Primary care faecal calprotectin testing in children with suspected inflammatory bowel disease: a diagnostic accuracy study

GPs' perspectives on diagnostic tests for children: a qualitative interview study

BACKGROUND

Most healthcare contacts for children in the UK occur in general practice. Diagnostic tests can be beneficial in narrowing differential diagnoses; however, there is substantial variation in the use of tests for children in general practice. Unwarranted variation in testing can lead to variation in quality of care and may exacerbate health inequities. To our knowledge, no previous study has tried to understand why variation in testing exists for children in general practice.

AIM

To explore GPs' perspectives on using diagnostic tests for children in primary care and the underlying drivers of variation.

DESIGN AND SETTING

Qualitative study in which semi-structured interviews were conducted with GPs and trainee GPs in England.

METHOD

Interviews were conducted with 18 GPs and two trainee GPs between April and June 2023. The interviews were transcribed and analysed using reflexive thematic analysis.

RESULTS

GPs reflected that their approach to testing in children differed from their approach to testing in adults: their threshold to test was higher, and their threshold to refer to specialists was lower. GPs' perceptions of test utility varied, including objective testing for asthma. Perceived drivers of variation in testing were intrinsic (clinician-specific) factors relating to their risk tolerance and experience; and extrinsic factors, including disease prevalence, parental concern and expectations of health care, workforce changes leading to fragmentation in care, time constraints, and differences in guidelines.

CONCLUSION

The findings of this study identify actionable issues for clinicians, researchers, and policymakers to address gaps in education, evidence, and guidance, reduce unwarranted differences in test use, and improve the quality of health care delivered to children in general practice.

Exploring the Diagnostic Spectrum of Children with Raised Faecal Calprotectin Levels

Faecal calprotectin (FC) is a marker of gut inflammation. The cause and relevance of raised FC in children outside the context of established inflammatory bowel disease (IBD) have had minimal attention. This study aimed to address this by carrying out a retrospective study on children with abnormal FC tests aged 4-17 years without established IBD in the South Island, New Zealand. Abnormal FC results were stratified: 51-249 μg/g, 250-499 μg/g, and 500+ μg/g, and participants were categorised into diagnostic groups. Data were collected on symptoms and diagnostic tests. Three-hundred and ten children had abnormal index FC results, with a mean age of 12.9 years, and a 55% proportion of females. The median FC was 125 μg/g; 71% had levels 51-249 μg/g and 21% had levels 500+ μg/g. Of those with FC 500+ μg/g, 89% either had infectious diarrhoea or were diagnosed with IBD at the time of, or subsequent to, the index FC. Alarm symptoms did not delineate between groups with FC 500+ μg/g. Abnormalities in platelet levels, abdominal ultrasound, and colonoscopy were more frequent for children diagnosed with IBD. Repeat FC test levels were significantly reduced except for those subsequently diagnosed with IBD. Abnormal FC levels for the majority were below the level indicative of mucosal inflammation. Repeat FC testing could play an important role in distinguishing between diagnoses.

Effect of faecal calprotectin testing on referrals for children with chronic gastrointestinal symptoms in primary care: study protocol for a cluster randomised controlled trial

INTRODUCTION

Children with chronic gastrointestinal symptoms are frequently seen in primary care, yet general practitioners (GPs) often experience challenges distinguishing functional gastrointestinal disorders (FGID) from organic disorders. We, therefore, aim to evaluate whether a test strategy that includes point-of-care testing (POCT) for faecal calprotectin (FCal) can reduce the referral rate to paediatric specialist care among children with chronic gastrointestinal symptoms. The study findings will contribute to improving the recommendations on FCal use among children in primary care.

METHODS AND ANALYSIS

In this pragmatic cluster randomised controlled trial, we will randomise general practices into intervention and control groups. The intervention group will use FCal-POCT when indicated, after completing online training about its indication, interpretation and follow-up as well as communicating an FGID diagnosis. The control group will test and treat according to Dutch GP guidelines, which advise against FCal testing in children. GPs will include children aged 4-18 years presenting to primary care with chronic diarrhoea and/or recurrent abdominal pain. The primary outcome will be the referral rate for children with chronic gastrointestinal symptoms within 6 months after the initial assessment. Secondary outcomes will be evaluated by questionnaires completed at baseline and at 3- and 6-month follow-up. These outcomes will include parental satisfaction and concerns, gastrointestinal symptoms, impact of symptoms on daily function, quality of life, proportion of children with paediatrician-diagnosed FGID referred to secondary care, health service use and healthcare costs. A sample size calculation indicates that we need to recruit 158 GP practices to recruit 406 children.

ETHICS AND DISSEMINATION

The Medical Research Ethics Committee (MREC) of the University Medical Center Groningen (The Netherlands) approved this study (MREC number: 201900309). The study results will be made available to patients, GPs, paediatricians and laboratories via peer-reviewed publications and in presentations at (inter)national conferences.

TRIAL REGISTRATION NUMBER

The Netherlands Trial Register: NL7690 (Pre-results).

Fecal Calprotectin in Combination With Standard Blood Tests in the Diagnosis of Inflammatory Bowel Disease in Children

Introduction: Fecal calprotectin (FC) is a useful non-invasive screening test but elevated levels are not specific to inflammatory bowel disease (IBD). The study aimed to evaluate the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FC alone or FC in combination with other standard blood tests in the diagnosis of IBD. Methods: Children aged <17 years who had FC (normal range <50 μg/g) measured and underwent endoscopy over 33 months in Christchurch, New Zealand were identified retrospectively (consecutive sampling). Medical records were reviewed for patient final diagnoses. Results: One hundred and two children were included; mean age was 12.3 years and 53 were male. Fifty-eight (57%) of the 102 children were diagnosed with IBD: 49 with Crohn's disease, eight with ulcerative colitis and one with IBD-unclassified. FC of 50 μg/g threshold provided a sensitivity of 96.6% [95% confident interval (CI) 88.3-99.4%] and PPV of 72.7% (95% CI 61.9-81.4%) in diagnosing IBD. Two children with IBD however were found to have FC <50 μg/g. Sensitivity in diagnosing IBD was further improved to 98.3% (95% CI 90.7-99.1%) when including FC >50 μg/g or elevated platelet count. Furthermore, PPVs in diagnosing IBD improved when FC at various thresholds was combined with either low albumin or high platelet count. Conclusion: Although FC alone is a useful screening test for IBD, a normal FC alone does not exclude IBD. Extending FC to include albumin or platelet count may improve sensitivity, specificity, PPV and NPV in diagnosing IBD. However, prospective studies are required to validate this conclusion.