Background and study aims:The usefulness of a new quick test for endoscopic diagnosis of adult-type hypolactasia was tested in duodenal biopsies.In this test,an endoscopic biopsy from the postbulbar duodenum is incuba...Background and study aims:The usefulness of a new quick test for endoscopic diagnosis of adult-type hypolactasia was tested in duodenal biopsies.In this test,an endoscopic biopsy from the postbulbar duodenum is incubated with lactose on a test plate,and a color reaction develops within 20 min as a result of hydrolyzed lactose(a positive result) in patients with normolactasia,whereas no reaction(a negative result) develops in patients with severe hypolactasia.Patients and methods:Two postbulbar duodenal biopsies were taken from 80 prospectively enrolled adult outpatients with dyspepsia.The biopsies were used for the Quick Lactase Test(Biohit PLC,Helsinki,Finland) and in biochemical disaccharidase(lactase,sucrase,and maltase) assays.In addition,the C/T-13910 genotype was determined from DNA extracted from gastric antral biopsies using polymerase chain reaction sequencing in genomic analysis of adult-type hypolactasia.Results:Twenty-one of 22 patients(95% ;95% CI,87-100%) with biochemical lactase activity < 10 U/g protein,but none of the 58 patients with lactase activity of 10 U/g protein or more had a negative result in the Quick Lactase Test.Seven of the 80 patients(9% ;95% CI,3-15%) had a Quick Lactase Test result that indicated mild hypolactasia(a mild color reaction) .All patients with celiac disease(n = 6) had a negative Quick Lactase Test result.Nine of 74 patients(six patients with celiac disease were excluded) had a CC-13910 genotype in genomic testing,indicating adult-type hypolactasia.All of them had negative test results with the Quick Lactase Test.Twenty-six patients had a TT genotype,indicating normolactasia,and none of these patients had a negative test result in the Quick Lactase Test.Six of 39 patients(15% ;95% CI,4-27%) with a CT genotype had a negative result in the Quick Lactase Test.Conclusions:The Quick Lactase Test effectively identifies patients with severe duodenal hypolactasia.In comparison with CC(adult-type hypolactasia) and TT individuals(normolactasia) ,the sensitivity and specificity of the Quick Lactase Test result was 100%.In comparison with biochemical lactase assays,the sensitivity and specificity of a negative Quick Lactase Test for indicating hypolactasia(lactase activity < 10 U/g protein) were 95%(95% CI,87-100%) and 100%,respectively.展开更多
文摘Background and study aims:The usefulness of a new quick test for endoscopic diagnosis of adult-type hypolactasia was tested in duodenal biopsies.In this test,an endoscopic biopsy from the postbulbar duodenum is incubated with lactose on a test plate,and a color reaction develops within 20 min as a result of hydrolyzed lactose(a positive result) in patients with normolactasia,whereas no reaction(a negative result) develops in patients with severe hypolactasia.Patients and methods:Two postbulbar duodenal biopsies were taken from 80 prospectively enrolled adult outpatients with dyspepsia.The biopsies were used for the Quick Lactase Test(Biohit PLC,Helsinki,Finland) and in biochemical disaccharidase(lactase,sucrase,and maltase) assays.In addition,the C/T-13910 genotype was determined from DNA extracted from gastric antral biopsies using polymerase chain reaction sequencing in genomic analysis of adult-type hypolactasia.Results:Twenty-one of 22 patients(95% ;95% CI,87-100%) with biochemical lactase activity < 10 U/g protein,but none of the 58 patients with lactase activity of 10 U/g protein or more had a negative result in the Quick Lactase Test.Seven of the 80 patients(9% ;95% CI,3-15%) had a Quick Lactase Test result that indicated mild hypolactasia(a mild color reaction) .All patients with celiac disease(n = 6) had a negative Quick Lactase Test result.Nine of 74 patients(six patients with celiac disease were excluded) had a CC-13910 genotype in genomic testing,indicating adult-type hypolactasia.All of them had negative test results with the Quick Lactase Test.Twenty-six patients had a TT genotype,indicating normolactasia,and none of these patients had a negative test result in the Quick Lactase Test.Six of 39 patients(15% ;95% CI,4-27%) with a CT genotype had a negative result in the Quick Lactase Test.Conclusions:The Quick Lactase Test effectively identifies patients with severe duodenal hypolactasia.In comparison with CC(adult-type hypolactasia) and TT individuals(normolactasia) ,the sensitivity and specificity of the Quick Lactase Test result was 100%.In comparison with biochemical lactase assays,the sensitivity and specificity of a negative Quick Lactase Test for indicating hypolactasia(lactase activity < 10 U/g protein) were 95%(95% CI,87-100%) and 100%,respectively.
