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P235 How useful are blood tests in the diagnosis of paediatric inflammatory bowel disease?

J. J. Ashton*1,2, F. Borca3, E. Mossotto2,3, H. Phan3, S. Ennis2, R. M. Beattie1

1Southampton Children's Hospital, Department of Paediatric Surgery, Southampton, UK, 2University Hospital Southampton, Department of Human Genetics and Genomic Medicine, Southampton, UK, 3University Hospital Southampton, NIHR Southampton Biomedical Research Centre, Southampton, UK

Background

Paediatric inflammatory bowel disease (PIBD) often presents following a significant diagnostic delay, with symptoms being attributed to other causes. Blood tests are a routine part of the work-up in children with chronic abdominal symptoms (pain, diarrhoea etc.). Normal tests cannot exclude PIBD, however normal results are often seen as reassuring to the clinician, sometimes incorrectly. We analysed blood results at diagnosis of PIBD over a 5-year period.

Methods

Patients diagnosed from 2013 to 2017 were identified from the Southampton-PIBD database. Blood results were obtained up to 100 days prior to diagnostic endoscopy. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), albumin, haemoglobin, platelets, packed cell volume (PCV), white cell count (WCC) and alanine transferase (ALT) were analysed. Statistical analysis was performed using Fisher exact test. Hierarchical clustering was performed following normalisation of data.

Results

In total, 256 patients were included, 151 had Crohn’s disease (CD), 95 had ulcerative colitis (UC), and 10 had IBD-unclassified. Median age at diagnosis 13.48 years, 36.7% (n = 94) female. The mean number of tests per patients was 7.5 (range 2–8). In PIBD, 9% presented with all normal bloods, 21.9% presented with normal CRP and ESR. Abnormal results were seen in all tests: ESR (56.4% of patients), CRP (53.4%), albumin (28%), haemoglobin (61.9%), platelets (55.6%), PCV (64.6%), WCC (22.7%), and ALT (7.2%). Abnormal inflammatory markers were more common in CD compared with UC (UC = 34% normal, CD = 15.6%, p = 0.0035). UC presented with all normal results more frequently than CD (UC = 14.4% normal, CD = 5.3%, p = 0.02). CRP, ESR, and platelets were significantly higher in CD compared with UC, albumin and haemoglobin were significantly lower (Table 1).

CRP (mg/l)ESR (mm/H)WCC (109/l)Haemoglobin (g/dl)Platelets (109/l)ALT (U/l)PCV (%)Albumin (g/dl)
All PIBD13219.2115424130.35935
Crohn’s disease24.5279.2115445120.3632
Ulcerative colitis4129.0117381.5160.35338
p-Value CD vs. UC0.000010.00010.1680.5960.00010.000010.5020.00001

Abstract P235 – Heatmap showing normalised data. Data were normalised by mean value and standard deviation. Red indicates a higher value, blue indicates a lower value, and white indicates a value of 0 (mean value). Black represents missing data.

Hierarchical clustering of patients based on normalised results revealed novel groupings enriched for CD and UC (Figure 1).

Conclusion

Most cases of PIBD present with more than one abnormal blood result, although 1/11 patients will present with all normal bloods and 1/5 will present with normal inflammatory markers. Diagnosis of PIBD cannot be excluded with normal blood results. Children with red flag symptoms may benefit from faecal calprotectin testing and prompt referral to specialist care regardless of blood results.