BlueCross BlueShield of Tennessee Medical Policy Manual

Genetic Testing for Lactase Insufficiency


Genetic testing of adults with suspected lactase insufficiency (e.g. PROMETHEUS LactoTYPE®) is proposed as an alternative to current diagnostic practices, which include hydrogen breath test (HBT), lactose tolerance blood test (LTT), and intestinal biopsy. Studies have demonstrated a high correlation between a single nucleotide polymorphism (SNP), C/T-13910 and lactase insufficiency.

Lactase is an enzyme necessary for the digestion of the sugar lactose found in dairy products. An insufficiency of lactase results in the malabsorption of lactose which may lead to symptoms of lactose intolerance such as abdominal pain, bloating, diarrhea and increased flatulence which are caused by bacterial fermentation of undigested lactose in the colon. Dietary restriction is adequate in most circumstances as the primary treatment for lactase insufficient individuals. These individuals who achieve satisfactory symptom control following dietary modifications do not require further diagnostic testing, however for the majority of individuals who do not achieve symptom control following dietary modifications, further diagnostic testing is indicated for the presence of other conditions that might cause symptoms similar to lactase deficiency.

The goal of treatment should be to ensure adequate nutrition for skeletal health.1 For patients with lactase insufficiency, dietary adjustment to restrict the consumption of foods containing lactose is the principal form of therapy. However, even lactose mal-digesters can usually tolerate small amounts of lactose (12g/d) with no or minimal symptoms. Lactase enzyme preparations are available for symptom relief but may not be effective in all individuals.




Currently there is insufficient evidence that the assessment of the genetic etiology of lactose intolerance would affect patient management or improve clinical outcomes.


Agency for Healthcare Research & Quality. (2010, February). Evidence Report/Technology Assessment No.192: Lactose intolerance and health (AHRQ Publication No. 10-E004). Retrieved July 2, 2013 from

BlueCross BlueShield Association. Medical Policy Reference Manual. (4:2015). Genetic testing for lactase insufficiency (2.04.94). Retrieved May 29, 2015 from BlueWeb. (40 articles and/or guidelines reviewed)

Mattar, R., de Campos, Mazo, D. F., & Carrilho, F. J. (2012). Lactose intolerance: Diagnosis, genetic, and clinical factors. Clinical and Experimental Gastroenterology, 5, 113-121. (Level 5 evidence)

Mendoza Torres, E., Varela Prieto, L. L., Villarreal Camacho, J. L., & Villanueva Torregroza, D. A. (2012). Diagnosis of adult-type hypolactasia/lactase persistence: Genotyping of single nucleotide polymorphism (SNP C/T-13910) is not consistent with breath test in Colombian Caribbean population. Arquivos de Gastroenterologia, 49 (1), 5-8. (Level 3 evidence)

Usai-Satta, P., Scarpa, M., Oppia, F., & Cabras, F. (2012). Lactose malabsorption and intolerance: What should be the best clinical management? World Journal of Gastrointestinal Pharmacology and Therapeutics; 3 (3), 29-33.  (Level 4 evidence)

Winifred S. Hayes, Inc. Genetic Testing Evaluation (GTE) Report. (2015, March). LactoTYPE. Retrieved June 9, 2015 from




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