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HelpTest Code LAB909 Non-Gestational 2HR Glucose Tolerance Test
Clinical Information
This test is intended for the diagnosis of diabetes mellitus in non-pregnant patients. It is to be used with a 75 g oral glucose load and includes a fasting plasma glucose sample (fasting defined as no caloric intake for 8 hours) and a plasma glucose sample obtained 2 hours post-75g oral glucose load.
Synonym
- GTF
- G2T
Profile Information
| Reporting Name | Available Separately | Always Reported |
|---|---|---|
| Glucose, Fasting (Non-Gestational) | Yes | Yes |
| Glucose Tolerance, 2Hr (Non-Gestational) | Yes | Yes |
Specimen Required
Preferred Container/Tube: Mint Green Top
Acceptable Container/Tube: Mint Green Top, Gold SST Top
Specimen Volume: 3 mL
Specimen Minimum Volume: 1 mL
Specimen Stability Information
Ambient: 8 hours
Refrigerated: 3 days
Rejection Due To
- Gross hemolysis
- Gross icterus
- Quantity not sufficient
- Quality not acceptable
Reference Values
Glucose, Fasting
70-125 mg/dL
Glucose Tolerance, 2 Hr
70-199 mg/dL
Interpretation
According to the American Diabetes Association's clinical practice recommendations, the diagnosis of diabetes mellitus can be made if either the fasting plasma glucose or the 2hr post-glucose samples meet or exceed 126 mg/dL or 200 mg/dL, respectively. The recommendations also note that in the absence of unequivocal hyperglycemia, the diagnosis requires two abnormal test results from the same sample or in two separate test samples.
The ADA criteria for prediabetes is a fasting plasma glucose of 100-125 mg/dL or 2hr post-glucose sample of 140-199 mg/dL.
Cautions
Falsely elevated glucose results may occur in patients taking Eltrombopag. In some cases of monoclonal gammopathies (especially Waldenstrom's macroglobulinemia with very high concentrations of IgM), glucose results may be unreliable.
Method Description
Photometric rate with hexokinase
Performing Lab
Clinical Lab UH
Clinical Lab University East
Clinical Lab Martha Morehouse
Clinical Lab Spielman
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 day
Reporting Name
Glucose, Fasting (Non-Gestational)
Glucose Tolerance, 2Hr (Non-Gestational)
CPT Code Information
82947
82950
LOINC Code Information
2345-7 x2