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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.
Submit With Order
ARUP Consult®
Disease Topics
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
Component Test Code*Component Chart NameLOINC
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Aliases
  • Disaccharide Absorption Test
  • Hydrogen Breath Test
  • Lactose Breath Test
  • LactoTYPE
  • Oral Lactose Tolerance
  • PROMETHEUS LactoType