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Test Code GTTPRENAT75G Glucose Tolerance, Prenatal, 75G, Serum or Plasma

Important Note

This test is a 2 hour prenatal glucose tolerance test using a 75 gram glucose solution.

Additional Codes

  • Expanse Test Name:Glucose Tolerance: Prenat 75G
  • Medinet Ref Code:GTT75
  • OV Code:CHEM*GTTPRENAT75G

Performing Laboratory

St. Lukes Hospital Laboratory

Methodology

Enzymatic/Hexokinase

Specimen Requirements

Patient Preparation:Patient should be fasting (8-14 hour).

 

Performance of Test:

1. Draw blood for a fasting glucose level.

2. Obtain 75 g of glucose solution.

3. If patient is <100 pounds, a smaller dose of glucose solution should be calculated by the laboratory.

4. Have patient consume glucose solution within 5 minutes.

5. Start timing from first sip.

6. Draw specimen at 1-,and 2-hours post glucose solution ingestion.

Note:  If patient cannot completely consume glucose solution (or cannot keep it down) or drinks part of the glucose solution and spills the rest, the test must be cancelled and rescheduled.

 

Specimen Collection:

Submit only 1 of the following specimens:
 
Plasma

Draw blood in a green-top (lithium heparin) plasma gel tube(s). Spin down and send 1 mL of lithium heparin plasma refrigerated.
Note:  1. Indicate time of draw and plasma on request form.
2. Label specimen appropriately (time of draw and plasma).
 
Serum
Draw blood in a serum gel tube(s). Spin down and send 1 mL of serum refrigerated.
Note:  1. Indicate time of draw and serum on request form.
2. Label specimen appropriately (time of draw and serum).

 

Unspun specimens must be transported at ambient temperature and arrive to the laboratory within one hour of draw.

Reference Values

Diagnostic criteria for the 75 g oral glucose tolerance are as follows:

≥92 mg/dL fasting

≥180 mg/dL at 1 hour

≥153 mg/dL at 2 hours

 

Any single value greater that these criteria is diagnostic of Gestational Diabetes.

Day(s) Test Set Up

Monday through Friday

Test Classification and CPT Coding

CPT: 82951 - 3 specimens