Sign In
Labcorp Oklahoma, Inc.
Test Directory


Index:

Glucose Tolerance (5 Hour) w/o Urine

Order Name GTT 5 HR
Test Number: 2002425
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 
Glucose 3 Hour Tolerance
Hexokinase 20437-0 
Glucose 4 Hour Tolerance
Hexokinase 26541-3 
Glucose 5 Hour Tolerance
Hexokinase 26543-9 
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 Daily 
Expected TAT 1-2 days  
Clinical Use There are no established guidelines, reference ranges or criteria, for the evaluation of a three hour, four hour or five hour specimen following a five hour glucose challenge. 
Notes For more information on this test, access our "Specialized Tests" section.
CPT Code(s) 82951, 82952x3
Lab Section Chemistry