title: Comparison of Quick Lactose Intolerance Test in duodenal biopsies of dyspeptic patients with single nucleotide polymorphism LCT-13910C>T associated with primary hypolactasia/lactase-persistence.
abstract: OBJECTIVE
  To analyze the usefulness of Quick Lactose Intolerance Test in relation to the genetic test based on LCT-13910C>T genotypes, previously validated for clinical practice, for primary hypolactasia/lactase-persistence diagnosis.
  
  
  METHODS
  Thirty-two dyspeptic patients that underwent upper gastrointestinal endoscopy entered the study. Two postbulbar duodenal biopsies were taken for the Quick test, and gastric antral biopsy for DNA extraction and LCT-13910C>T polymorphism analysis. DNA was also extracted from biopsies after being used in the Quick Test that was kept frozen until extraction.
  
  
  RESULTS
  Nine patients with lactase-persistence genotype (LCT-13910CT or LCT-13910TT) had normolactasia, eleven patients with hypolactasia genotype (LCT-13910CC) had severe hypolactasia, and among twelve with mild hypolactasia, except for one that had LCT-13910CT genotype, all the others had hypolactasia genotype. The agreement between genetic test and quick test was high (p<0.0001; Kappa Index 0.92). Most of the patients that reported symptoms with lactose-containing food ingestion had severe hypolactasia (p<0.05). Amplification with good quality PCR product was also obtained with DNA extracted from biopsies previously used in the Quick Test; thus, for the future studies antral gastric biopsies for genetic test would be unnecessary.
  
  
  CONCLUSIONS
  Quick test is highly sensitive and specific for hypolactasia diagnosis and indicated those patients with symptoms of lactose intolerance.
authors: Department of Gastroenterology, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors: Rejane
authors: R
authors: Mattar
authors: Anibal
authors: A
authors: Basile-Filho
authors: Rafael
authors: R
authors: Kemp
authors: José Sebastião dos
authors: JS
authors: Santos
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D004386:Duodenum / Q000473:pathology; D004415:Dyspepsia / Q000473:pathology; D020776:Endoscopes, Gastrointestinal; D005260:Female; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D043322:Lactase / Q000172:deficiency; D007785:Lactose / Q000235:genetics; D007787:Lactose Intolerance / Q000175:diagnosis* / Q000235:genetics; D007789:Lactose Tolerance Test / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011517:Prothrombin Time; D012189:Retrospective Studies; D011795:Surveys and Questionnaires
chemical_list: D043322:Lactase; D007785:Lactose