- LACTOSE TOLERANCE
- Start Date
- Expiration Date
- CPT Codes
- 82951; 82952 x 2
- Reference Test
- Transport Info
- Fasting Required?
- Patient Instructions
Adults: fasting at least 12 hours
Infants less than 2 years old: fasting 2 hours
- Reference Range
An increase of 30 mg/dL over the fasting glucose level is considered normal
A rise of 20-30 mg/dL is inconclusive
An increase of less than 20 mg/dL is evidence for a deficiency of intestinal lactase
Detect the presence of normal or deficient lactase activity in the small intestinal mucosa.
The lactose tolerance test is used to detect the presence of normal or deficient lactase activity in the small intestinal mucosa. This enzyme splits lactose into galactose and glucose that can be absorbed into the blood.The fasting patient is given an oral dose of lactose. Serum specimens are analyzed for glucose before and at timed intervals after drinking the lactose. Glucose is measured by any of the standard glucose procedures.If normal lactase activity is present, the lactose will be hydrolyzed to glucose and galactose, and the serum glucose values will be similar to a glucose tolerance curve. With lactase deficiency the tolerance curve is flat with a rise not exceeding 20 mg/dL higher than the fasting level.