Sign In
St. John Health System
Lab Catalog


Index:

Glucose Tolerance (2 Hour) w/o Urine

Order Name GTT 2 HR
Test Number: 2016800
Revision Date 05/20/2021
Test Name Methodology LOINC Code
Glucose Fasting
Hexokinase 1558-6 
Glucose 1 Hour Tolerance
Hexokinase 20438-8 
Glucose 2 Hour Total
Hexokinase 20436-2 
SPECIMEN REQUIREMENTS
Specimen Specimen Volume (min) Specimen Type Specimen Container Transport Environment
Preferred 1 mL (0.5) Plasma Sodium fluoride (gray top) Refrigerated
Alternate 1 1 mL (0.5) Plasma Lithium Heparin PST (Light Green Top) Refrigerated
Alternate 2 1 mL (0.5) Serum Clot Activator SST Refrigerated
Instructions Fasting overnight and during test. Patient may have water.
Draw fasting specimen. Adults: Give 75 grams of glucola. Children: Adjusted amount of glucola to be calculated by lab. Call (918) 744-2500.
Stability: Ambient 8 hours, Refrigerated 7 days, Frozen 1 month
Fluoride preserved plasma samples are stable at room temperature for 24 hours
GENERAL INFORMATION
Testing Schedule Mon - Fri 
Expected TAT 1-2 days  
Clinical Use Criteria for Diagnosis of Diabetes from the American Diabetes Association recommends Random plasma glucose >200 mg/dl with symptoms (polyuria, polydypsia, and unexplained weight loss) repeated to confirm on subsequent day, or Fasting plasma glucose>126 mg/dl repeated to confirm, or 2hr plasma glucose <200 mg/dl post 75g glucose challenge repeated to confirm. 
Notes For more information on this test, access our "Specialized Tests" section.
CPT Code(s) 82951
Service Provided By Labcorp Oklahoma, Inc.
Lab Section Chemistry