Abbrev Code:GLU   
Order Code:LAB3502Order Name:Glucose
Order Instructions:UMMC: For stat/conditional newborn recheck of critically LOW glucose by meter, order GLUCW and collect in capillary tube.
Synonyms:Two Hour Postprandial
Methodology:Roche: UV Test: Enzymatic reference method with hexokinase
Vista: Bichromatic endpoint
Woodwinds: Hexokinase
CPT Codes: 82947 x1, 82947 x1
Turnaround Time:Performed and reported 24 hours/day.
Special Instructions:Glucose will decrease 5 -10 mg/dL/hour in an unprocessed tube as a result of glycolysis. Collection in a gray top (NaF + K-oxalate) tube will halt glycolysis after 2 hours and preserve the glucose level for 24 hours.
Associated Links:

Roche Go Live Schedule

Collection Instructions

Optimal Volume:2.5 mL
Minimum\Peds Volume:0.6 mL
Collection Instructions:Chemistry Tests Containers Chart
Patient Preparation:Instructions
  • Do not eat 10-12 hours before your appointment if you are coming in fasting for labs on lipids, cholesterol or glucose (sugar). This does not apply to pregnant women.
  • Water, tea or black coffee (with nothing added) is okay.
  • Do not drink other fluids, diet soda or chew gum.
  • If you have concerns about taking your medications, please send a message by clicking on Secure Messaging, Message Your Care Team.
Causes for Rejection:Specimen not separated from cells within 2 hours of collection (4 hours for Home Health specimens). Gray top tube not received within 24 hours of collection.

Processing and Shipping

Specimen Processing:Process within 2 hours (4 hours for Home Health specimens). Centrifuge and aliquot 1.25 mL, 0.2 mL minimum. Store in refrigerator.
Shipping Instructions:Ship at refrigerated temperature.
Stability:Roche and Vista: Once separated from cells: 8 hours at room temperature; 72 hours refrigerated.
Test Performed at or Referral Lab Chemistry  (Clinics, CSC Maple Grove, Roche-CSC Mpls, Roche-Grand Itasca, Roche-Lakes, Roche-Northland, Roche-Range, Roche-Ridges, Roche-Southdale, Roche-St. John's, Roche-UMMC East, Roche-UMMC West, Woodwinds)


Critical Range:Basic, Electrolyte and Renal Panels Critical Values and Reference Ranges
Reference Range:Basic, Electrolyte and Renal Panels Critical Values and Reference Ranges

While either a fasting glucose or oral glucose tolerance test (OGTT) can be used to diagnose pre-diabetes or diabetes, the ADA recommends the fasting glucose because it is easier, faster and less expen­sive to perform.

A fasting glucose level between 100 and 125 mg/dL signals pre-diabetes or impaired fasting glucose (IFG). A patient with a fasting glucose level of 126 mg/dL or higher has diabetes.

A two-hour glucose level between 140 and 199 mg/dL on the OGTT signals pre-diabetes or impaired glucose tolerance (IGT). If the two-hour glucose level is 200 mg/dL or higher, the patient has diabetes.

Patients with IFG and/or IGT now are referred to as having “pre-dia­betes,” indicating their relatively high risk for developing diabetes.

For more information, see
















200 mg/dL





199 mg/dL


140 mg/dL





126 mg/dL


139 mg/dL




125 mg/dL


100 mg/dL





99 mg/dL

























Diagnostic Ranges





Click HERE to Report test errors or omissions.
*If no email program is associated with this computer, please contact:
[email protected] for TestID: 532"