GLUCOSE TOLERANCE 1 HR GESTATIONAL

Test Code

LAB2718

Quest Code

8477

CPT Codes
82950

Preferred Specimen

1 mL plasma collected in a fluoride/oxalate (gray-top) tube

Patient Preparation
Fasting is not required

Minimum Volume

0.5 mL

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

The patient is given a 50 g dose of glucose and a single blood specimen is obtained one hour later. Serum and plasma submissions must be separated from cells.

Note: The test should be performed between weeks 24 and 28 of gestation.

Transport Container

Fluoride/oxalate (gray-top)

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

Note: Serum and plasma submission must be separated from cells

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

Report Available

1-4 days

Limitations

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

Reference Range

<135 mg/dL

Clinical Significance

A value of 135 mg/dL or greater indicates the need for a full diagnostic, gestational glucose tolerance performed in the fasting state to determine if the patient has gestational diabetes.

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.