Epic Code LAB1230278 Glucose Tolerance, 2 hour test, 75g (Gestational Diabetes)

Important Note

For outpatient collection: Providers please instruct patient to arrive at least 3 hours prior to the lab closing to ensure there is enough time to complete the test.
- List of Laboratory Locations and Hours
This test is recommended and only available for PREGNANT patients.
Fasting specimen required - A fasting glucose specimen will be drawn.

Test Name Alias

Oral Glucose | GTT | OGTT

Interface Order Alias

Currently not available

Ordering Instructions

This test is recommended as a follow-up or confirmatory test for an abnormal One Hour Post (50 gram) OGTT.

This test is recommended and only available for PREGNANT patients.

For safety and accuracy of testing, patients are encouraged to have Oral Glucose Tolerance Tests (OGTT) performed at one of our Outpatient Service Centers.

Collection Instructions

A fasting glucose specimen will be drawn.
The patient is given a 75 gram oral glucose load.
Another specimen is drawn 1 hour and then 2 hours later.
GlucoCrush^TM, the glucola drink used in Spectrum Health Grand Rapids Laboratory does not contain gluten.

Specimen Collection: Blood

Container(s): 4.5 mL Mint Green Top (Lithium Heparin Gel) or 5.0 mL Gold Top (Serum Separator-SST Gel)

Preferred Volume to Collect: 4.5 mL

Minimum Volume to Collect: 1.0 mL

Capillary collect ok? Yes

Microtainer acceptable: Yes

Collection Instructions:

Fasting specimen required
Avoid hemolysis
After collection, gently invert tube 8-10 times.
Specimen should be processed within 2 hours – See Processing Instructions.

Processing Instructions (Laboratory, Outpatient or Off-site collection)

Processed Specimen: Plasma or Serum
Centrifuge/Spin: Yes
Aliquot: Yes
Processes Minimum Volume: 0.5 mL Plasma or Serum
Processing Instructions:
- Plasma is preferred specimen type
- Green Tube/Plasma: Centrifuge within 1 hour after collection.
- Gold Tube/Serum: Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours.
- Minimum plasma/serum volume: 0.5 mL
Transport Temperature: Refrigerated

Specimen Stability

Ambient: 8 hours

Refrigerate: 72 hours

Frozen: aliquot plasma/serum for longer storage

Laboratory Retention: 72 hours

Test Frequency

Available daily, usual TAT 1 day.

Reference Range

Glucose Fasting: 70-99 mg/dL

Glucose 1 Hour Post 75g: ≤180 mg/dL

Glucose 2 Hour Post 75g: 50-139 mg/dL

Performing Department

Chemistry

Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI
Corewell Health Lakeland St. Joseph Laboratory, St. Joseph, MI

Methodology

Enzymatic

CPT

82951

CDM Code

3018295101

Epic Test ID

123002002

LOINC