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Test Code GLC Glucose

Specimen and Container/Tube

Specimen Type: Plasma

Preferred Specimen: Li-Heparin Mint Green Top

Other Acceptable specimens: Serum/Gold Top, Serum/Red Top, Plasma/Lavendar K2 Top, Plasma/NaF/Na2EDTA, Plasma/KF/Na2EDTA, Plasma/NaF/K-Oxalate

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

Collect specimen per standard collection procedure and send to laboratory immediately.  Samples must be received within 2 hours of collection.

 

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples must be centrifuged within 30 min of collection.
  • Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
  • Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
  • Samples must be sent refrigerated at 2-8oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are clotted or grossly hemolyzed.
  • Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.
  • Samples left at room temperature should not be used.

Reference Values

 

Test

Age

Sex

Reference Range

Glucose

All

All

Fasting: 60-99 mg/dL

Non-Fasting: 60 - 139 mg/dL

 

Note: Reference range based on in-house studies, recommendations from Tietz Textbook of Clinical Chemistry, and Roche product literature.  

Critical Values

Analyte

Unit

Low

High

Age

Glucose

mg/dL

<40

>500

>14 days

Glucose

mg/dL

<30

>300

≤ 14 days

CPT Codes

82947

LOINC Codes

2345-7

Volume

Preferred Volume: 0.5 mL

Minimum Volume: 0.2 mL

Specimen Stability

Storage Temperature

Stability

Room temperature

Spun - 8 hours*

Unspun - 6 hours**

Refrigerated

Spun - 3 days

Unspun - 6 hours**

Frozen

 Not Acceptable

Note: 

*Specimen received spun greater than 8 hours from collection will be cancelled with the following comment: "Specimen Rejected: Specimen too old for analysis".

 

**Specimen received unspun between 2 - 6 hours from collection will be run and results will be reported with the following comment: "Interpret with caution.  Glucose decreases by ~5.0% per hour and may be significantly falsely decreased for uncentrifuged blood received greater than 2 hours after collection.  The rate of decrease might be greater for patients with elevated white blood counts."

 

**Specimen received unspun greater than 6 hours from collection will be cancelled with the following comment: "Specimen Rejected: Inappropriate Specimen Handling".

Collection Instructions

Collect specimen per standard laboratory collection procedures. 

 

Test Components

Glucose
 

Clinical Indications

Most frequent cause of hyperglycemia is diabetes mellitus resulting from a deficiency in insulin secretion or action. A number of seconday factors also contribute to elevated blood glucose levels. These include pancreatitis, thyroid dysfunction, renal failure and liver disease. Hypoglycemia is less frequently observed. A variety of conditions may cause low blood glucose levels such as insulinoma, hypopituitarism or insluin induced hypoglycemia.

Methodology

Enzymatic Method with hexokinase (Roche Diagnostics)

Additional Information

  • Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
  • When blood is drawn and permitted to clot and to stand uncentrifuged at room temperature, the average decrease in serum glucose is approximately 7% in one hour (0.28 to 0.56 mmol/L or 5 to 10 mg/dL). This decrease is the result of glycolysis. Glycolysis can be inhibited by collecting the specimen in fluoride tubes.
  • Patients can be fasting or non-fasting.
  • Also included in Basic Metabolic Panel KPNL, Comprehensive Metabolic Panel CPNL, ER Panel I STKG, Renal Function Panel RPNL, CMP for chronic lymphocytic leukemia (CPNL FOR CLL PATIENTS ONLY) SSTCP, BMP for chronic lymphocytic leukemia (KPNL FOR CLL PATIENTS ONLY)  SSTKP

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

 

STAT Turnaround Time: 1 hour

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Synonyms/Keyword Search

Sugar

Last Review Date

8/19/2024

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