Glucose Tolerance Test, 3 Specimens (75g) : 18927

Test Code

GTT3AU or 18927

CPT Codes
82951

Includes

Glucose: Fasting, 1-Hour, 2-Hour

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 and 2 hours later. Label each with the specific draw time.

Serum and plasma submissions must be separated from cells.

Transport Container

Preferred Specimen
Three - 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

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

Reference Ranges

Glucose, Fasting 65-91 mg/dL

Glucose, 1-Hour <180 mg/dL

Glucose, 2-Hour <153 mg/dL

ADA/IADPSG Guidelines: One or more values greater than the above reference intervals are diagnostic of gestational diabetes. Fasting plasma glucose ≥126 mg/dL indicates overt diabetes in pregnancy.

Clinical Significance

Plasma glucose levels may be abnormally high (hyperglycemia) or abnormally low (hypoglycemia). Glucose measurements are used in the diagnosis and treatment of carbohydrate metabolic disorders.

Performing Laboratory
med fusion

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.