Laboratory Lab results are too important to go anywhere else.

Glucose, Serum or Plasma

Blood Sugar (Random Blood Sugar, Fasting Blood Sugar)

Test Codes

Random Glucose: EPIC: LAB5062, GLU   Fasting Glucose: EPIC: LAB5053, GLFAS

Department

Chemistry

Instructions

• Record the exact time of draw on the tube.
• Specify if the specimen is fasting or random.
• Fasting Glucose: Patient should be fasting 8-12 hours prior to specimen collection.

Specimen Collection Criteria

FOR EC AND INPATIENT SAMPLE COLLECTION ONLY:

Preferred Sample:  One Light Green Top Plasma Separator Tube (PST)(Minimum Whole Blood: 4.0 mL)

Acceptable Sample:  One Gold Top SST (Minimum Whole Blood:  4.0 mL)

FOR PHYSICIAN OFFICE/OUTREACH SAMPLE COLLECTION:

COLLECT:  One Gold Top SST (Minimum Whole Blood:  4.0 mL)

Also acceptable: One Gray-top Potassium Oxalate/Sodium Fluoride tube. (Minimum Whole Blood: 4.0 mL) 

Contact Laboratory for acceptability of other tube types. 
See Minimum Pediatric Specimen Requirements for Microtainer^® collection.

Physician Office/Draw Specimen Preparation

• Let SST specimens clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged SST tube within two hours of collection. (Minimum: 0.5 mL)
• Maintain Gray-top tubes refrigerated (2-8°C or 36-46°F) prior to courier transport. (Minimum: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged SST tube or Gray-top tube, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

• Grossly hemolyzed specimens.
• Inadequately centrifuged Microtainers^® or Gold-top tubes.
• Red-top tubes with serum not separated from cells within two hours of collection.
• Gray-top tubes that are not received within 24 hours of the time of collection.

In-Lab Processing

Let SST specimens clot 30-60 minutes. Centrifuge SST, Gray-top tubes, or Microtainers^® to separate serum or plasma from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Gray-top Tubes
Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Plasma Specimens (Aliquots)
Room Temperature (20-26°C or 68-78.8°F): 2-4 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 7 days

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Canton Chemistry Laboratory
Dearborn Chemistry Laboratory
Farmington Hills Chemistry Laboratory 
Grosse Pointe Chemistry Laboratory 
Lenox Main Laboratory
Livonia Main Laboratory
Royal Oak Automated Chemistry Laboratory 
Troy Chemistry Laboratory
Taylor Chemistry Laboratory
Trenton Chemistry Laboratory
Wayne Chemistry Laboratory 

Performed

Sunday – Saturday, 24 hours a day.
STAT results available within 1 hour of receipt in the Laboratory.
Routine results available within 24 hours.

Reference Range

Fasting: 70-99 mg/dL.
Random: 70-139 mg/dL.

Fasting Glucose:

70-99 mg/dL	Normal
100-125 mg/dL	Impaired fasting glucose*
126 mg/dL or Greater	Diabetic*

* The Expert Committee on the Diagnosis and Classification of Diabetes Mellitus recommends that in the absence of unequivocal hyperglycemia with acute metabolic decompensation, a diagnosis of diabetes should be confirmed. Confirmation by a fasting glucose is the preferred diagnostic test.

Test Methodology

Enzymatic, Spectrophotometry.

Interpretation

In a normal individual plasma/serum glucose levels vary only slightly during a 24 hour period and are usually in the range of 45-130 mg/dL. Following a meal the glucose increase is rarely greater than 10-15 mg/dL and a 2 hour pc value should be less than 140 mg/dL. However, following a 75g glucose load (as in glucose tolerance test), the increase in plasma glucose in a healthy middle-aged subject may be 20-50 mg/dL higher than if the same amount of carbohydrate was given as a meal. In healthy individuals over 65 yrs, a random glucose may increase to 180 mg/dL. In IDDM plasma glucose may fluctuate by as much as 150 mg/dL following food intake.

Hyperglycemia is most commonly due to either type 1 or 2 diabetes mellitus, but may occur with other major endocrine diseases (eg. Cushing's disease, acromegaly), drugs (eg. steroids) and pancreatic disease.

Hypoglycemia is probably best diagnosed by Whipple's triad:

1. Signs/symptoms, often precipitated by fasting.
2. Plasma/serum glucose less than 45 mg/dL.
3. Symptoms relieved by administration of glucose.

In older diabetic subjects signs and symptoms of hypoglycemia may occur at levels greater than 45 mg/dL. Causes of hypoglycemia include reactive, drug or ethanol-induced, factitious, insulinoma, adrenocortical insufficiency, hypopituitarism and massive liver disease.

If serum or heparinized plasma is left in contact with blood cells for extended periods, glucose will be metabolized. Glucose levels decrease by about 5-7% or 7 mg/dL/hour at room temperature in normal specimens containing normal numbers of RBC's and WBC's.

CAUTION (Grosse Pointe Only): Interference from Sulfasalazine & Sulfapyridine – The glucose assay used at Beaumont Laboratory (Siemens VISTA®) is subject to interference by the drugs sulfasalazine and sulfapyridine.  Sulfasalazine is the accepted treatment for inflammatory bowel disease, ulcerative colitis, Crohn’s disease, rheumatoid arthritis, inflammatory arthritis and uveitis. Sulfapyridine is used occasionally for dermatitis herpetiformis and related skin disorders when alternative treatment is unsuitable. Falsely depressed or falsely elevated results may occur on samples from patients taking Sulfasalazine or Sulfapyridine. Venipuncture should occur before drug administration. Baseline values before administration of sulfasalazine or sulfapyridine would not be affected.

Clinical Utility

Glucose measurements are used in the diagnosis and management of disorders of carbohydrate metabolism; these include diabetes mellitus, neonatal hypoglycemia, idiopathic hypoglycemia, and pancreatic islet cell tumors.

CPT Codes

82947
LOINC:  5792-7

Contacts

Last Updated

1/9/2024