ARUP's Laboratory Test Directory
| 0020542: Glucose Tolerance Test |
| Test Mnemonic: GTT | |
|
Methodology: Enzymatic
Performed: Sun-Sat Reported: Within 24 hours |
| Specimen Required: | |
|
Collect: Two timed specimens (fasting and 120 minutes): one 4 mL gray (sodium fluoride/potassium oxalate) per time point. Patient should be fasting for at least eight hours prior to collection of fasting specimen.
Transport: 1 mL plasma per time point at 2-8°C. (Min: 0.2 mL per time point) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 0.2 mL plasma, per time point at 2-8°C. Remarks: Separate plasma from cells and refrigerate ASAP. Stability: After separation from cells: Ambient: 24 hours; Refrigerated: 1 week; Frozen: 1 year |
|
| Reference Interval: |
| Glucose (fasting and 120 min). Interpretation available on consultation with medical director. |
| Note: | |
| Administer 75 g glucose load with 450 mL water. The patient should be fasting for at least eight hours prior to start of test, should remain inactive, and receive nothing by mouth (including tobacco) during test period. A small sip of water or ice is permissible. Reasons for invalid results include emesis and conditions which delay stomach emptying. |
| CPT Code(s): | |
| 82947 Glucose, fasting; 82950 Glucose, post challenge |