Glucose Tolerance Test, 2 Specimens (75g)

Test Code

35181

CPT Codes
82947, 82950 <br>** This test is not available for Maryland, New York, or Rhode Island patient testing. **

Includes

Fasting, 2-Hour glucose

Preferred Specimen

1 mL plasma collected in each of two separate fluoride/oxalate (gray-top) tubes

Patient Preparation
Fasting required. Fasting is defined as no consumption of food or beverage other than water for at least 8 hours before specimen collection.

Minimum Volume

0.5 mL [x2]

Other Acceptable Specimens

Plasma collected in each of two separate lithium heparin or sodium heparin (green-top) tubes • Serum collected in each of two separate serum separator tubes (SST), received spun

Instructions

Immediately after a fasting specimen is obtained, have patient ingest a 75 g load of glucose. Draw subsequent specimen 2 hours later. Label each specimen with the specific draw time.

Note: Serum and plasma submissions must be separated from cells.

Transport Temperature

⁠⁠⁠⁠⁠⁠⁠Fluoride/Oxalate plasma/Serum: Room temperature
Heparinized plasma: Refrigerated (cold packs)

Specimen Stability

Plasma (Fluoride/Oxalate)
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days

Plasma (Heparin)
Room temperature: 48 hours
Refrigerated: 7 days
Frozen: 28 days

Serum
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Unspun serum separator tubes • Red-top or non-plasma separator green-top tubes • Anticoagulants other than lithium heparin, sodium heparin or fluoride/oxalate

Methodology
Spectrophotometry (SP)

Setup Schedule

Set up: Tues-Sun; Report available: 1 day

Limitations

Glucose levels may be depressed if sample is left on clot for an excessive length of time.

Clinical Significance

This test is used for the routine diagnosis of diabetes in children and the non-pregnant adult. For pregnant females see test "Glucose Tolerance Test, Gestational, 4 Specimens (100 g)". 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 ideal body weight, up to 75 g glucose. The diagnosis of diabetes is made if the fasting glucose is ≥126 mg/dL or if the 2-hour specimen is ≥200 mg/dL.

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.