Lactose Tolerance
0020407
 
Ordering Recommendation
Mnemonic
LACTOL
Methodology
Quantitative Enzymatic
Performed
Sun-Sat
Reported
Within 24 hours
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
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.  
Collect
Gray (sodium fluoride/potassium oxalate). Collect separate tube for each timed point.  
Specimen Preparation
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)  
Storage/Transport Temperature
Refrigerated.  
Unacceptable Conditions
 
Remarks
 
Stability
After separation from cells: Ambient: 24 hours; Refrigerated: 72 hours; Frozen: 1 year  
Reference Interval
Fasting glucose: 64-128 mg/dL
Normal lactose tolerance: 20-30 mg/dL elevation in glucose over fasting level after 50 g lactose load.
Interpretive Data
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.
Note
Glucose in whole blood at room temperature undergoes glycolysis at a rate of approximately 7 percent each hour.
CPT Code(s)
82951; add 82952 x2 each specimen beyond three
Components
Cross References
  • Disaccharide Absorption Test
  • Hydrogen Breath Test
  • Lactose Breath Test
  • LactoTYPE
  • Oral Lactose Tolerance
  • PROMETHEUS LactoType