Glucose Tolerance Test, Pregnancy
Also known as: GTT PRG
Use
This test evaluates maternal glucose metabolism by measuring glucose concentrations at fasting and at multiple timed intervals (60, 120, and 180 minutes) following a 100 g glucose load during pregnancy. It assists in diagnosing gestational diabetes based on ADA or ACOG guidelines and supports clinical interpretation of glucose tolerance in pregnant patients.
Special Instructions
Administer 100 g glucola; do not mix with water unless directions indicate. Patient must fast at least eight hours prior to the test, remain inactive, and have nothing by mouth (including tobacco) during the test period except a small sip of water or ice is permissible. Reasons for invalid results include emesis and delayed gastric emptying.
Limitations
Interpretive limits vary based on population, glucose dose, and time of collection after glucose administration. Published guidelines from the American Diabetes Association or the American Congress of Obstetricians and Gynecologists should be consulted for interpretive values.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL per time point
Minimum Volume
0.2 mL per time point
Container
Gray (sodium fluoride/potassium oxalate) tube; separate tube for each timed specimen
Collection Instructions
Collect 4 timed specimens (fasting, 60, 120, and 180 minutes); separate tube for each timepoint
Patient Preparation
Patient should fast for at least eight hours prior to collection
Storage Instructions
Refrigerated
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Ambient: 24 hours |
| Refrigerated | 1 week |
| Frozen | 1 year |
Other tests from different labs that may be relevant