Laboratory:
Chemical Pathology
Referral Laboratory:
MiChart Code:
GLUCOSE TOLERANCE, 3HR, OBSTETRICS [LAB1880]
Soft Order Code:
GL3OB
Synonyms:
Container:
SST is preferred specimen. Grey top tube is acceptable if centrifuged and separated within 24 hrs. of collection.
Normal Volume:
0.5 mL serum
Minimum Volume:
0.25 mL serum
Offsite Collection:
Collect blood in an SST tube from a fasting patient. Administer 100 gm Glucola. Instruct patient to finish drinking the Glucola within 5 minutes of the time he or she starts drinking and not to eat anything except a few sips of water after finishing the Glucola. Collect blood in an SST tube exactly 1, 2, and 3 hours after the patient finished drinking the Glucola. Centrifuge within 4 hours of collection, aliquot serum into a plastic vial and refrigerate. If specimen cannot be centrifuged at client site, please arrange for delivery to MLabs within 3 hours of specimen collection. Label vials appropriately (Fasting, 1 HR, 2 HR, and 3HR).
Onsite Collection (Michigan Medicine Hospitals Only):
Collect blood in an SST tube from a fasting patient. Administer 100 gm Glucola. Instruct patient to finish drinking the Glucola within 5 minutes of the time he or she starts drinking and not to eat anything except a few sips of water after finishing the Glucola. The patient should remain seated and not smoke throughout the test. Collect blood in an SST tube exactly 1, 2 and 3 hours after the patient finished drinking the Glucola. Centrifuge, aliquot serum into plastic vials and refrigerate. Label vials appropriately (Fasting, 1 HR, 2 HR, and 3HR)
Days Set Up:
Daily, 24 hours
Analytic Time:
2 hours
Reference Range:
*Reference ranges may change over time. Please refer to the original patient report when evaluating results.
American Diabetes Association Reference Ranges: Gestational Diabetes, 50 g load, 1 hr: <140 mg/dl Gestational Diabetes, 100 g load: Fasting <95 mg/dl; 1 hr <180 mg/dl; 2 hr <155 mg/dl; 3 hr <140 mg/dl Fasting <95 mg/dL
Test Usage:
Determine glucose level, monitor insulin therapy, evaluate carbohydrate metabolism
Test Methodology:
Hexokinase, NADH Endpoint
Additional Information:
A 3-hour Glucose Tolerance test specifically for Obstetrics. This will not replace the current Glucose 3-hour tolerance test (GLUC3), but will be offered in addition, to provide clarity in the interpretation of the results. Specimen labels are generated at time intervals appropriate for the collection times to be drawn One label to be used for fasting sample at the beginning of testing (GLF) and additional labels to be used on the samples drawn at 1 hour (GL60), 2 hours (GL120), and 3 hours (GL180) after Glucola administration).
LOINC:
GL3OB Glucose Tolerance, 3 hour, Obstetrics LOINC : 50586-7 OGLF Glucose, Fasting OB GTT LOINC: 1558-6 OG60 Glucose, 1-hour OB GTT LOINC: 20438-8 OG120 Glucose, 2-hour OB GTT LOINC: 25667-7 OG180 Glucose, 3-hour OB GTT LOINC: 20437-0
CPT Code:
82951
Fee Code:
20521
Specimen Retention:
4 days
Test ID:
5865