Glucose Tolerance Test, Postprandial/2-Hour

Glucose Tolerance Test, Postprandial/2-Hour

Test Code

4637
82947
CPT Code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.
4637
82947
CPT Code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.
Ordering Restrictions may apply. Please provide SERVICE AREA INFORMATION to find available tests you can order.
Not offered in Quest Nichols Institute - Chantilly, VA | Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano | Quest Nichols Institute -San Juan Capistrano, CA. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection is not available in your area through Quest Mobile.

Clinical Significance

Glucose Tolerance Test, Postprandial/2-Hour -

Postprandial glucose levels may be abnormally high in patients with gestational diabetes. If results are positive, and the patient is pregnant, a 3-hour oral glucose tolerance test should be performed for confirmation of gestational diabetes.

Test Resources

None found for this test
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Test Details

Methodology

Spectrophotometry (SP)

Reference Range(s)

<140 mg/dL

LOINC® Codes, Performing Laboratory

Service Area must be determined

Methodology

Spectrophotometry (SP)

Reference Range(s)

<140 mg/dL
Service Area must be determined

Preferred Specimen(s)

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

Alternative Specimen(s)

Plasma from fluoride/oxalate (gray-top), lithium heparin (green-top) or sodium heparin (green-top) tube in a plastic screw-cap vial • Serum (separated from cells immediately) in a plastic screw-cap vial • Spun SST

Minimum Volume

0.5 mL

Collection Instructions

Specimen is obtained 2 hours following a meal. Serum and plasma submissions must be separated from cells.

Transport Container

Fluoride/oxalate (gray-top) tube

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

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

Setup Schedule

Service Area must be determined
1 mL plasma collected in a fluoride/oxalate (gray-top) tube
Plasma from fluoride/oxalate (gray-top), lithium heparin (green-top) or sodium heparin (green-top) tube in a plastic screw-cap vial • Serum (separated from cells immediately) in a plastic screw-cap vial • Spun SST
0.5 mL
Specimen is obtained 2 hours following a meal. Serum and plasma submissions must be separated from cells.
Fluoride/oxalate (gray-top) tube
Room temperature
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
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
Service Area must be determined
Ordering Restrictions may apply. Please provide SERVICE AREA INFORMATION to find available tests you can order.
Not offered in Quest Nichols Institute - Chantilly, VA | Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano | Quest Nichols Institute -San Juan Capistrano, CA. Please provide SERVICE AREA INFORMATION to find available tests you can order.
In-home collection is not available in your area through Quest Mobile.
Test Details

Clinical Significance

Test Resources

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.

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