A recent study (Z Kiss et al. JPGN 2018; 67: 6-12) provides more data on normative values for eosinophil counts in the GI tract. For their report, the authors reviewed 3 databases for a systematic search of the literature. They screened 1316 abstracts but found only 8 articles with complete/relevant data. Among these 8 articles, data regarding each segment of the GI tract was present in as few as 3 articles and as many as 6 articles. The authors provide confidence intervals (CIs) and prediction intervals (PIs); the latter account for the wider uncertainty due to insufficient data.
Normal eosinophil cell number per high-power field (HPF area = 0.2 mm squared):
- Duodenum 8.26 with CI 4.71-11.8 and PI of 0 to 20.57
- Terminal ileum 11.52 with CI 7.21-15.83 and PI of 0 to 60.64
- Cecum 14.12 with CI 9.05-19.19 and PI of 0 to 38.64
- Ascending colon 13.25 with CI 8.65-17.86 and PI of 0 to 35.42
- Transverse colon 11.52 with CI 7.80-15.23 and PI of 0 to 25.85
- Descending colon 10.32 with CI 7.22-13.42 and PI of 0 to 49.10
- Sigmoid colon 8.80 with CI 6.82-10.77 and PI of 0 to 32.49
- Rectum 7.39 with CI 4.20-10.59 and PI of 0 to 22.33
- The authors note that eos/HPFis a flawed measurement due to technical parameters of the microscope. Some HPFs are bigger than others –this could affect eosinophil count up to 5-fold. The authors specify an HPF to be =0.2 mm squared.
- Obtaining appropriate mucosal samples for normal number of eosinophil counts can be difficult. Even patients with functional disorders like irritable bowel syndrome and nonulcer dyspepsia could have abnormal numbers of eosinophils.
My take: These numbers of expected eosinophil counts for pediatric histology are a good starting point. The prediction intervals remain large due to insufficient data.
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