Detect lactase deficiency.
Within 24 hours
Recommend drawing specimens for baseline (fasting), 30 minutes, 60 minutes, 120 minutes, and 180 minutes after lactose load (lactose may be obtained from a hospital pharmacy). Fasting patient should be given 50 g lactose in 200-300 mL water consumed in 5 to 10 minutes. Note: If severe lactase deficiency is suspected, the dose should be lowered.
Gray (sodium fluoride/potassium oxalate). Collect separate tube for each timed point.
Separate plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL plasma for each time point to individual ARUP Standard Transport Tubes. (Min: 0.5 mL per timed determination)
After separation from cells: Ambient: 24 hours; Refrigerated: 72 hours; Frozen: 1 year
Fasting glucose: 64-128 mg/dL
Normal lactose tolerance: 20-30 mg/dL elevation in glucose over fasting level after 50 g lactose load.
A less than 20 mg/dL increase in glucose over the fasting level, with gastrointestinal symptoms after a lactose load is considered abnormal and consistent with lactase deficiency.
Glucose in whole blood at room temperature undergoes glycolysis at a rate of approximately 7 percent each hour.
82951; 82952 x2
|Component Test Code*||Component Chart Name||LOINC|
- Disaccharide Absorption Test
- Oral Lactose Tolerance