Excellent agreement between genetic and hydrogen breath tests.pdf

Excellent agreement between genetic and hydrogen breath tests for lactase deficiency and the role of extended symptom assessment D. Pohl1,2*, E. Savarino1,3, M. Hersberger4, Z. Behlis1, B. Stutz1, O. Goetze1, A. v. Eckardstein5, M. Fried1 and R. Tutuian1,6 1Division of Gastroenterology and Hepatology, University Hospital Zurich, Raemistrasse 100, 8091 Zu?rich, Switzerland 2Division of Gastroenterology and Hepatology, Digestive Disease Center, Medical University of South Carolina, Charleston, SC, USA 3Division of Gastroenterology and Hepatology, University of Genoa, Genoa, Italy 4Division of Clinical Chemistry and Biochemistry, University Children’s Hospital, Zurich, Switzerland 5Institute of Clinical Chemistry, University Hospital Zurich, Zurich, Switzerland 6University Clinic for Visceral Surgery and Medicine, Bern University Hospital, Inselspital, Bern, Switzerland (Received 15 September 2009 – Revised 1 March 2010 – Accepted 15 March 2010 – First published online 19 April 2010) Clinical manifestations of lactase (LCT) deficiency include intestinal and extra-intestinal symptoms. Lactose hydrogen breath test (H2-BT) is considered the gold standard to evaluate LCT deficiency (LD). Recently, the single-nucleotide polymorphism C/T213 910 has been associated with LD. The objectives of the present study were to evaluate the agreement between genetic testing of LCT C/T213 910 and lactose H2-BT, and the diagnostic value of extended symptom assessment. Of the 201 patients included in the study, 194 (139 females; mean age 38, range 17–79 years, and 55 males, mean age 38, range 18–68 years) patients with clinical suspicion of LD underwent a 3–4 h H2-BT and genetic testing for LCT C/T213 910. Patients rated five intestinal and four extra-intestinal symptoms during the H2-BT and then at home for the following 48 h. Declaring H2-BT as the gold standard, the CC213 910 genotype had a sensitivity of 97 % and a specificity of 95 % with a k of 0·9 in diagnosing LCT deficiency. Patie