Gestational Glucose Tolerance Diagnostic Test (Three-hour, ACOG Recommendations)
Also known as: Glucose Tolerance, Gestational Diabetes (Fasting, One-hour, Two-hour, and Three-hour)
Use
Diagnose gestational diabetes
Special Instructions
Not provided.
Limitations
The test may not be suitable for patients with known diabetes mellitus or those under physiological stress such as surgery or infection. Accurate results require strict adherence to fasting and preparation protocols. Incorrect specimen labeling with collection time intervals can lead to test rejection.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 50586-7 - GTT 3h Pnl SerPl
- 1558-6 - Glucose p fast SerPl-mCnc
- 1501-6 - Glucose 1h p 100 g Glc PO SerPl-mCnc
- 1514-9 - Glucose 2h p 100 g Glc PO SerPl-mCnc
- 1530-5 - Glucose 3h p 100 g Glc PO SerPl-mCnc
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL serum each tube
Minimum Volume
0.5 mL serum each tube
Container
Gel-barrier tubes (4)
Collection Instructions
Draw fasting blood sugar before administering 100-gram glucose, then draw blood at one, two, and three hours. Separate serum from cells within 45 minutes of venipuncture. Label each tube with patient's name and collection time interval (i.e., fasting, one-hour, two-hour, and three-hour).
Patient Preparation
Eat a diet of 150+ grams of carbohydrate for three days prior. Fast for at least 8 hours before the test.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Frozen gray-top tube; stressed patient; specimens not labeled with collection time intervals.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
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