Glucose, Fasting
Test Mnemonic
GLF
CPT Codes
- 82947 - QTY (1)
LOINC ®
1558-6
Aliases
- FBS
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Plasma | Potassium oxalate/sodium fluoride (Gray) | Centrifuge and refrigerate. | Aliquot into CCL aliquot tube |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 0.3 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 24 hours |
| Refrigerated | After removed from cells: 72 hours |
| Frozen | Unnacceptable |
Days Performed
Sun - Sat
Turnaround Time
8 hours
Methodology
| Name | Description |
|---|---|
| Glucose Hexokinase |
Reference Range
| Glucose, Fasting | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Years | 99 Years | Normal | 74 - 99 | mg/dL | Years | 99 Years | Normal | Pre-Diabetes: 100 - 125 | mg/dL | Years | 99 Years | Normal | Diabetes: > 125 | mg/dL | Years | 99 Years | Urgent | > 500 | mg/dL | Urgent | Inpatient only: 40-49 mg/dL (First result only, once every 24 hours.) | mg/dL | Years | 99 Years | Critical | < 40 | mg/dL |
Special Info
Patient should be fasting at least 8 hours prior to the test.
Clinical Info
Evaluation of glycemia American Diabetes Association guidelines state that a diabetes mellitus diagnosis is preliminarily made when the fasting plasma glucose meets or exceeds 126 mg/dL. In the absence of unequivocal hyperglycemia, results should be confirmed with repeat testing. Patients are at increased risk for diabetes mellitus (prediabetes) when the fasting glucose is 100 to 125 mg/dL.