Home
HelpGlucose Tolerance Test
Methodology
Ortho Vitros 7600, Integrated System, Colormertic
Performing Laboratory
Heart of the Rockies Regional Medical Center
Specimen Requirements
Specimen Type: Serum/plasma
Container/Tube:
Serum: Yellow top or red top
Plasma: Light-green top
Specimen Volume: Full tube
Collection Instructions:
1. The patient should be fasting for 8 hours before testing, and should arrive at 7:30am.
2. First draw a fasting glucose specimen. If the fasting glucose is >150 mg/dL, notify physician to be sure it is okay to continue with the test.
3. Have the patient drink the 75g glucose beverage and note the time.
4. At one hour after the glucose is given, draw the one-hour specimen. Subsequent specimens are obtained at 2 hours, 3 hours, etc. according to the Physician’s request.
Specimen Transport Temperature
Ambient/Refrigerated OK
Reference Values
|
Fasting Glucose Values |
Interpretation |
| <100 mg/dL | Normal fasting glucose |
| 100-125 mg/dL | Impaired fasting glucose |
| ≥126 mg/dL |
Provisional diagnosis of DM (confirmation required)* |
| 2-Hour Post Load Glucose | |
| <140 mg/dL | Normal glucose tolerance |
| 140-199 mg/dL | Impaired glucose tolerance |
| ≥200 mg/dL |
Provisional diagnosis of DM (confirmation required)* |
*Glucose values should be interpreted in the context of clinical findings
Criteria for the etiologic classification of Diabetes Mellitus (DM) according to the Expert Committee on the Diagnosis and Classification of DM:
-Symptoms and a random glucose of >200 mg/dL or
-A fasting glucose concentration of >126 mg/dL or
-Two hour glucose concentration of >200 mg/dL
Test Classification and CPT Coding
82951-3 specimens
82959-Each additional specimen beyond 3