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Glucose Tolerance Test, 5 Specimens : 10560
Test CodeGTT5AU or 10560
Alias/See Also
4 HR Glucose Tolerance, Non-pregnant,Glucose Tolerance 4 HR, Non-pregnant,4 HR GTT (5 Specimens)
CPT Codes
82951, 82952x2
Instructions
Patient Preparation: Fasting required. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before testing.
Immediately after a fasting specimen is obtained, have patient ingest a 75 g load of glucose. Draw subsequent specimens 1, 2, 3 and 4 hours later. Label each with the specific draw time.
Note: Serum and plasma submissions must be separated from cells
Immediately after a fasting specimen is obtained, have patient ingest a 75 g load of glucose. Draw subsequent specimens 1, 2, 3 and 4 hours later. Label each with the specific draw time.
Note: Serum and plasma submissions must be separated from cells
Transport Container
Preferred Specimen
Five - 1 mL plasma specimens collected in fluoride/oxalate (gray-top) tubes
Alternative Specimens
Plasma from fluoride/oxalate (gray-top) tube in a plastic screw-cap vial, Serum (separated from cells immediately) in a plastic screw-cap vial, Spun SST® , Plasma from lithium heparin (green-top) tube in a plastic screw-cap vial, Plasma from sodium heparin (green-top) tube in a plastic screw-cap vial
Minimum Volume: 0.5 mL for each specimen
Five - 1 mL plasma specimens collected in fluoride/oxalate (gray-top) tubes
Alternative Specimens
Plasma from fluoride/oxalate (gray-top) tube in a plastic screw-cap vial, Serum (separated from cells immediately) in a plastic screw-cap vial, Spun SST® , Plasma from lithium heparin (green-top) tube in a plastic screw-cap vial, Plasma from sodium heparin (green-top) tube in a plastic screw-cap vial
Minimum Volume: 0.5 mL for each specimen
Transport Temperature
Room temperature.
Specimen Stability
Serum
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days
Whole blood (gray-top) tube
Room temperature: 24 hours
Refrigerated: 72 hours
Frozen: Unacceptable
Sodium fluoride plasma
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Heparinized plasma
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 28 days
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days
Whole blood (gray-top) tube
Room temperature: 24 hours
Refrigerated: 72 hours
Frozen: Unacceptable
Sodium fluoride plasma
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Heparinized plasma
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Unspun serum or plasma separator tube (SST® or PST), Red-top or green-top tube (serum or heparinized plasma not separated from cells), Anticoagulants other than lithium heparin, sodium heparin or fluoride/oxalate
Methodology
Spectrophotometry
Setup Schedule
Sunday - Saturday
Report Available
1 day
Reference Range
Glucose Value (mg/dL)
Interpretation Fasting 1 Hr Tolerance 2 Hr Tolerance
Normal <100 Not established <140
Impaired Fasting 100-125
Impaired Tolerance 140-199
Diabetes ≥126* ≥200*
*Must be confirmed by testing on a subsequent day.
Clinical Significance
For appropriate interpretation of this test, the patient must fast overnight and ingest a 75 g load of glucose, immediately after a fasting specimen is obtained. (for children, the glucose load is 1.75 g/Kg of body weight, up to 75). The diagnosis of diabetes is made if glucose exceeds 200 mg/dL in the 2 hour specimen and in any preceding specimen
Performing Laboratory
med fusion
