GLUCOSE TOLERANCE NON GESTATIONAL 2 HR

Test Code

LAB169

Quest Code

35181

CPT Codes
82947, 82950

Includes

Fasting, 2-Hour glucose

Preferred Specimen

Two - 1 mL plasma specimens collected in 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 for each specimen

Other Acceptable 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

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 Container

Fluoride/oxalate (gray-top) tubes

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 (SP)

Setup Schedule

Tues-Sat

Limitations

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

Reference Range

American Diabetes Association Diagnostic Criteria for Diabetes Mellitus
Glucose Value (mg/dL)
Interpretation	Fasting	2-Hr Tolerance
Normal	<100	<140
Impaired Fasting	100-125
Impaired Tolerance		140-199
Diabetes	≥126*	≥200*

*Must be confirmed by testing on a subsequent day.

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.

Performing Laboratory

Quest Diagnostics-Lenexa

10101 Renner Blvd

Lenexa , KS 66219-9752

Last Updated: August 13, 2021

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.