Glucose Tolerance Test, 3 specimens (75 g)
Use
This test involves obtaining a fasting glucose specimen, administering a 75 g oral glucose load, and obtaining subsequent glucose measurements at 1 hour and 2 hours. It is used to assess how the body processes glucose and supports the diagnosis of prediabetes or diabetes in children and non-pregnant adults.
Special Instructions
Fasting is required—typically no food or beverages except water for at least 8 hours prior to testing. After the fasting draw, administer the glucose load and collect timed specimens at 1 and 2 hours, labeling each tube with the draw time.
Limitations
Interpretation may be affected by improper fasting, mistimed sample collection, or specimen handling issues. Pediatric dosing is weight-adjusted at 1.75 g/kg up to a maximum of 75 g glucose load.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL per sample
Minimum Volume
0.5 mL per sample
Container
fluoride/oxalate tube
Collection Instructions
Obtain fasting plasma in fluoride/oxalate tube, then administer 75 g glucose and collect at 1 hour and 2 hours, label each with draw time.
Patient Preparation
Fasting at least 8 hours (no food or drink except water). Pediatric dose: 1.75 g glucose per kg ideal body weight up to 75 g.
Causes for Rejection
Use of serum separator or unacceptable anticoagulants (non‑fluoride/oxalate)
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 7 days |