Gestational Glucose Tolerance, 3 Hour

Test Code

LAB164

Alias/See Also

3 Hour GTT
GTT3

CPT Codes
82952

Preferred Specimen

Light green top tube (lithium heparin plasma)

Minimum Volume

Whole blood: 600 uL (one full light-green-top microtainer or two full red-top microtainers).
Serum/plasma: 300 uL plasma

Other Acceptable Specimens

Gold top (serum separator tube) or Red Top

Instructions

Fasting required.

Draw fasting glucose. If the results come back less than 126 mg/dl, give the patient 100 grams of Glucola. Draw additional specimens at 1, 2, and 3 hours. Label each specimen with specific draw time. (4 specimen total) LAB: Centrifuge and analyze promptly. Serum acceptable. Separate specimens within 30 minutes of collection

Specimen Stability

Ambient: up to 24 hours.
Refrigerated: 7 days.
Frozen: 1 year

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

Hemolyzed, contaminated, not enough volume

Setup Schedule

Everyday

Report Available

Same day

Limitations

In fresh specimens, catalase released from the lysis of red blood cells causes a negative bias in glucose results. The degree of bias is proportional to the degree of hemolysis. A negative bias of up to 10% may be observed with a level of hemolysis associated with a hemoglobin concentration of 250 mg/dL.

Reference Range

Glucose, Fasting - 3 Hr GTT: Reference range: 65-94 mg/dL
Glucose, 1 Hr - 3 Hr GTT: Reference range: 65-179 mg/dL
Glucose, 2 Hr - 3 Hr GTT: Reference range: 65-154 mg/dL
Glucose, 3 Hr - 3 Hr GTT: Reference range: 65-139 mg/dL

Performing Laboratory
Hoag Newport/Hoag Irvine

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.