Glucose Tolerance Test
0020542
Ordering Recommendation
Use to diagnose gestational diabetes mellitus, diabetes mellitus, or impaired glucose tolerance.
Submit With Order
Mnemonic
GTT
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
Patient should fast for at least eight hours prior to collection of fasting specimen.  
Collect
Collect 2 timed specimens (fasting and 120 minutes). Gray (sodium fluoride/potassium oxalate). Collect separate tube for each timed specimen.  
Specimen Preparation
Separate plasma from cells and refrigerate within 2 hours of collection. Transfer 1 mL plasma per time point to individual ARUP Standard Transport Tube. (Min: 0.2 mL/time point)  
Storage/Transport Temperature
Refrigerated.  
Unacceptable Conditions
 
Remarks
 
Stability
After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 1 year  
Reference Interval
Glucose (fasting and 120 min). Interpretation available on consultation with medical director.
Interpretive Data
Note
Administer 75 g glucola. Do not mix with water unless directions on product label indicate to do so. The patient should be fasting for at least eight hours prior to start of test, should remain inactive, and receive nothing by mouth (including tobacco) during test period. A small sip of water or ice is permissible. Reasons for invalid results include emesis and conditions which delay stomach emptying.
CPT Code(s)
82947; 82950
Components
Cross References
  • Blood Glucose
  • Blood Sugar
  • Fasting Blood Glucose
  • Fasting Blood Sugar
  • Fasting Plasma Glucose
  • FBG
  • FBS
  • FPG
  • GLU
  • GTT
  • OGTT
  • Oral Glucose Tolerance Test