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HelpTest Code LAB23322 Glucose Tolerance, 2 Hour - Adult Outpatient
Department
Chemistry
Collection Requirements
This is the standard 2 hour glucose tolerance test used in the diagnosis of diabetes mellitus in adult males and non-pregnant females.
8 hour fast is required
Patient should be on a high carbohydrate diet for 72 hours prior to the test.
Draw the fasting glucose as soon as possible after patient’s arrival.
Give 75 grams of prepared dextrose and then draw a glucose specimen one hour after prepared dextrose and 2 hours after prepared dextrose.
Verify each collection for the exact draw time. Do not accept default draw times.
Primary Collection Container
Green PST (Lithium Heparin)
Alternate Collection Container
Green Microtainer PST
Transport
Plasma refrigerated
Preferred Transport Temperature
Refrigerated
Processing
Centrifuge and refrigerate.
Separate from cells if testing is delayed more than 2 hours.
Deliver to Chemistry ASAP.
Stability
Refrigerated: 72 hours
Minimum Testing Volume
0.5 mL
Reference Range
By report
Methodology
Hexokinase (HK) Roche c503
Performed
Sunday – Saturday
Reported
As completed
CPT Codes
Gross hemolysis.
Delay in separating cells from plasma.
Unacceptable Conditions
Test includes: Fasting, 1 hour and 2 hour glucose, and an interpretation guideline for the diagnosis of Diabetes Mellitus.