Diabetes Mellitus Glucose Tolerance Test, fasting*
Methodology
Colorimetric Absorbance
Performing Laboratory
Rutland Regional Medical Center Laboratory
Specimen Requirements
Patient Preparation: Patient must be on a normal diet for 3 days prior to testing, and be fasting for at least 8 to 14 hours prior to test.
Specimen Type: Blood
Container/Tube:
Preferred: Light-green top (lithium heparin gel)
Acceptable: Gold top, serum gel
Specimen Volume: Full tube
Specimen Minimum Volume: 2 mL
Collection Instructions:
1. Draw a fasting specimen.
2. Give patient a 75 g dose of glucose beverage, noting time of ingestion (patient must drink entire beverage within 5 minutes).
3. Draw specimens at 2-hours post ingestion of glucose beverage.
4. Label specimens with times of draw.
5. Send specimens in original tubes.
6. If there is a delay in transport of >1 hour, centrifuge tubes.
Specimen Transport Temperature
Refrigerated
Reference Values
Gluc Baseline 50 to 99 mg/dL
Gluc 2 Hour 50 to 139
Day(s) Performed
Monday - Saturday
Analytical Time:
1 day
Test Classification and CPT Coding
82947
82950
Interface Codes
Diabetes Mellitus Glucose Tolerance Test, fasting L701006
Gluc Baseline L700999 & L802593
Gluc 2 Hour L701000 & L802594