Community‐based Case‐Control Study of Childhood Chronic Abdominal Pain: Role of Selected Laboratory Investigations

Objective: To compare laboratory investigation results in children with chronic abdominal pain and in healthy control children. Our hypothesis was that parasitic infection was not a causal factor for chronic abdominal pain and that there would be no difference in leukocyte count, hemoglobin level, or erythrocyte sedimentation rate (ESR) between the 2 groups. Patients and Methods: Children with chronic abdominal pain and healthy control children (5–15 years) were recruited from the practices of 6 primary care pediatricians in Toronto, Canada. Stool samples were analyzed for ova and parasites, and serum samples were used to estimate leukocyte count, hemoglobin, and ESR. A standardized questionnaire was used to gather social, demographic, and clinical information. Results: A total of 157/200 children (79%) provided samples. Children with chronic abdominal pain were more likely to be female than were control children. Stool samples were positive for parasitic infection in 15 children, with no difference in prevalence between children with chronic abdominal pain (6/87; 7%) and healthy control children (9/70; 13%); P = 0.28). The mean (standard deviation) leukocyte count in children with chronic abdominal pain was 7.4 × 10 9 /L (2.03), compared with 8.3 × 10 9 /L (1.82) in healthy control children. No child had a leukocyte count above 20 × 10 9 /L. The mean (SD) hemoglobin in children with chronic abdominal pain was 131 g/L (8.4), compared with 130 g/L (9.2) in healthy control children. Last, the median ESR in children with chronic abdominal pain was 5 mm/hour, compared with 3 mm/hour in control children. Conclusions: The study findings suggest that in the absence of alarming symptoms and signs, parasitic infection is not a causal factor for chronic abdominal pain and that routine screening tests (leukocyte count, hemoglobin, ESR) are not useful.