Weight may affect routine blood test results in children, researchers say

A child’s weight may influence the results of many routine blood tests, research published in the Journal of Clinical Endocrinology & Metabolism (17 December 2019) has suggested^[1]
.

Researchers tested blood samples provided by 1,332 apparently healthy children and teenagers for 35 biochemical markers. Serum biomarker levels were compared among subjects who were normal weight, overweight and obese, as determined by their body mass index (BMI) scores (range: 13.4–65.0kg/m²).

The researchers also examined the influence of BMI, waist circumference and waist-to-height ratio on blood test results. They found that results for 24 of the 35 tests were affected by the child’s weight status after adjusting for age and sex, including liver function tests, and inflammatory marker, lipid and iron levels.

The researchers acknowledged that altered biochemical marker levels among overweight and obese children and teens may reflect subclinical disease and warned that including them in reference ranges may lead to inappropriate interpretation.

“Normative ranges are often stratified by age and sex, but our findings suggest that weight status may be an additional factor to consider when developing normative ranges to improve interpretation of blood test results,” said Victoria Higgins, a clinical biochemistry fellow at the University of Toronto and lead author on the study.