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23195 Glucose Tolerance - Fasting and 2HR

Glucose Tolerance - Fasting and 2HR
Test Code: GTADA
Synonyms/Keywords
Glucose Tolerance, Fast & 2Hr ​
Useful For
The primary use of the oral glucose tolerance test is the diagnosis of diabetes mellitus.  The test measures the ability of the individual to remove an added glucose load from the circulation.  Blood samples are obtained at timed intervals after the ingestion of the test glucose load.​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)

Yes

8 Hours​

 Plasma/Serum​Lithium-heparin Plasma Separator (PST)​, Serum Separator Tube (SST)
Lithium or Sodium-heparin Green Top (GTT),
Red Top Tube (RTT), Gray Top Tube (GYTT)
1 mL​0.3 mL​ ​
Collection Processing Instructions
**See Glucose Tolerance Guidelines for test protocol and interpretation.
 
Fluoride/oxalate is the preferred preservative if analysis is delayed more than one hour.
Usual Adult Glucose Test Dose = 75 g glucose. The glucola must be consumed within a 5 minute interval; sipping water is permitted. Patients should be ambulatory and on a high carbohydrate diet for at least 3 days prior to the test. Patient must be fasting for 8 hours prior to start of the tolerance test.​
Specimen Stability Information
Specimen Type Temperature Time
Plasma​/Serum ​ Ambient​ 5 days​
Refrigerate​ 7 days​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Chippewa Falls​ ​Monday through Friday ​Less than 2 hours​ ​Modified Hexokinase Method/Siemens Dimension
​Diagnostic Treatment Center ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Eau Claire ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Flambeau Hospital ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Ladysmith Medical Center ​​Monday through Sunday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Lakeview Medical Center ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 2 hours​ Hexokinase-UV/NAD Endpoint Assay/Beckman AU
​Merrill ​Monday through Saturday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Neillsville​Monday through Sunday​Less than 2 hours​​Modified Hexokinase Method/Siemens Dimension
​Stevens Point ​​Monday through Friday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Wausau ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Wisconsin Rapids ​​Monday through Friday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
Reference Range Information
Performing Location Reference Range
All Performing Sites See Interpretation​
Interpretation
American Diabetes Association Guidelines for the diagnosis of diabetes mellitus in non-pregnant patients are as follows (Diabetes Care Jan 2004, S5-S10):
Two separate days in which any two of the following events occur:
fasting glucose >=100 mg/dL or,
random glucose >=200 mg/dL or,
2 hour glucose following glucose load >=200 mg/dL.​
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82947 ​ ​ ​ Glucose​ ​
82950 ​ ​ ​  Glucose, post dose ​ ​
Synonyms/Keywords
Glucose Tolerance, Fast & 2Hr ​
Ordering Applications
Ordering Application Description
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)

Yes

8 Hours​

 Plasma/Serum​Lithium-heparin Plasma Separator (PST)​, Serum Separator Tube (SST)
Lithium or Sodium-heparin Green Top (GTT),
Red Top Tube (RTT), Gray Top Tube (GYTT)
1 mL​0.3 mL​ ​
Collection Processing
**See Glucose Tolerance Guidelines for test protocol and interpretation.
 
Fluoride/oxalate is the preferred preservative if analysis is delayed more than one hour.
Usual Adult Glucose Test Dose = 75 g glucose. The glucola must be consumed within a 5 minute interval; sipping water is permitted. Patients should be ambulatory and on a high carbohydrate diet for at least 3 days prior to the test. Patient must be fasting for 8 hours prior to start of the tolerance test.​
Specimen Stability Information
Specimen Type Temperature Time
Plasma​/Serum ​ Ambient​ 5 days​
Refrigerate​ 7 days​
Useful For
The primary use of the oral glucose tolerance test is the diagnosis of diabetes mellitus.  The test measures the ability of the individual to remove an added glucose load from the circulation.  Blood samples are obtained at timed intervals after the ingestion of the test glucose load.​
Reference Range Information
Performing Location Reference Range
All Performing Sites See Interpretation​
Interpretation
American Diabetes Association Guidelines for the diagnosis of diabetes mellitus in non-pregnant patients are as follows (Diabetes Care Jan 2004, S5-S10):
Two separate days in which any two of the following events occur:
fasting glucose >=100 mg/dL or,
random glucose >=200 mg/dL or,
2 hour glucose following glucose load >=200 mg/dL.​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Chippewa Falls​ ​Monday through Friday ​Less than 2 hours​ ​Modified Hexokinase Method/Siemens Dimension
​Diagnostic Treatment Center ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Eau Claire ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Flambeau Hospital ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Ladysmith Medical Center ​​Monday through Sunday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Lakeview Medical Center ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 2 hours​ Hexokinase-UV/NAD Endpoint Assay/Beckman AU
​Merrill ​Monday through Saturday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Neillsville​Monday through Sunday​Less than 2 hours​​Modified Hexokinase Method/Siemens Dimension
​Stevens Point ​​Monday through Friday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Wausau ​Monday through Sunday​ ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
​Wisconsin Rapids ​​Monday through Friday ​Less than 2 hours​ ​​Modified Hexokinase Method/Siemens Dimension
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82947 ​ ​ ​ Glucose​ ​
82950 ​ ​ ​  Glucose, post dose ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.