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HelpTest Code GTT4 Glucose Tolerance Test 4 HR
Additional Codes
Epic EAP: LAB165
Epic Description: GLUCOSE TOLERANCE, 4 HOURS
Collection Limitations
This test may be started between 7:30 a.m. and 12 noon.
Specimen Type
Blood
Specimen Required
| Collection Container | Preferred Volume | Minimum Volume | |
|---|---|---|---|
| Preferred |
Gray, Sodium Fluoride & Potassium Oxalate |
4.0 mL | 1.0 mL |
| Alternate | Green, Lithium Heparin with Inert Gel OR Gold, Clot Activator with Inert Gel | 4.0 mL | 1.0 mL |
Instructions for Collection and Transport
The first collection is a fasting collection. All remaining collections are collected AFTER appropriate administration of a dextrose drink at specified timed intervals for the duration of the test.
Centrifuge specimen ASAP. Specimen should be centrifuged within 2 hours of collection if not collected in a grey top tube. For specimens needing transport to a central lab, if collected in a non-gel grey top tube, aliquot plasma into plastic vial after centrifugation. Transport refrigerated on freeze packs. If holding overnight, aliquot serum/plasma from the clot/gel into plastic vial and refrigerate.
Home Health agencies: Transport to laboratory within 2 hours of collection for centrifguation if not collected in a grey top tube since glucose in whole blood specimens is subject to degradation if not stabilized in sodium fluoride.
Aliquot Requirements
Plasma or Serum
Optimum 1.0 mL
Minimum 0.5 mL
Performing Lab
Chemistry Lab
Assay Frequency
24 hours
Routine Turnaround Time
1 day
CSR Storage Requirements
Centrifuge within 2 hours of collection and deliver to laboratory. If separated from cells, Glucose is stable for 2 days at room temperature and 7 days refrigerated.
CPT Code Information
82951
82952
Patient Preparation
Patient must be fasting. After a fasting blood glucose sample is collected, the patient is given a quantity of glucose determined by the patient’s height & weight. The patient should not eat or drink anything (including gum & mints) after the administration of glucose except water. Blood glucose levels will be drawn at specified timed intervals depending on the duration of the test. At the termination of the test, the patient will be allowed to have a meal. This test will take approximately 4 hours. The patient should remain in the Venipuncture waiting area for the duration of this test.