Aim: The aim of the present study was to compare the Biohit Lactose Intolerance Quick Test (BLIQT) to the criterion standard biochemical duodenal lactase (DL) activity assay in the paediatric population using standard statistical comparative tests.
Methods: Using standard Olympus endoscopes, 2 postbulbar duodenal biopsies were taken from 38 prospective children (0-16 years) from June 2008-May 2009 at a single tertiary paediatric gastroenterology unit. The biopsies were used for the BLIQT and for biochemical disaccharides assay.
Results: Thirty-eight children (19 boys) of median age 5.45 years (0.3-14.8 years) underwent the combined BLIQT and disaccharidase testing. We subdivided the group into those who had biopsies with a larger endoscope (XQ, n = 26) and those who had a smaller endoscope (XP, n = 12) and thus a smaller biopsy forcep. When using a larger endoscope, the BLIQT showed a sensitivity of 100%, specificity of 86%, and positive and negative predictive value of 57.1% and 100%, respectively, on comparing it with DL. With a smaller endoscope, the BLIQT had a sensitivity of 100%, specificity of 80%, positive predictive value of 50%, and a negative predictive value of 100%.
Conclusions: As in adult studies, the sensitivity and negative predictive value of the BLIQT was 100%. The specificity too appears to be high but variable, probably because of smaller biopsies obtained, and may warrant the need for 2 biopsies. The high sensitivity, specificity, and negative predictive value of the BLIQT for indicating hypolactasia make it an effective point-of-care test for paediatric hypolactasia.