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Test Code LAB82 Glucose, Plasma

Additional Codes

Glucose Fasting - LAB81

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

Note: This test is also available as part of LAB17, Comprehensive Metabolic Panel (CMP); LAB15, Basic Metabolic Panel (BMP); and LAB19, Renal Function Panel. See Common Panel Test Combinations to avoid duplicate requests if needed.

 

Patient Preparation: Eating affects results. Be sure to determine if fasting (>8 hours) or random specimen after meal is required

Collection Container/Tube:

Preferred: Mint green-top lithium heparin (MNTGRN LiHep) tube

Acceptable: Green samplette/microtainer, plain red-top tube, Gold SST gel tube, or Lavender-top (EDTA) tube

Submission Container/Tube: If specimen is coming from outside facility unprocessed, collect 3.0 mL of whole blood in a gray-top (potassium oxalate/sodium fluoride) tube. If collected in a microtainer, plain red-top tube or lavender-top tube aliquot processed sample into a plastic vial for transport (labeling with specimen type).

Specimen Collection Volume: 1.0 mL (minimum 0.6 mL)

Special Instructions: Send to lab promptly.

 

Sample Rejection

Mislabled or unlabeled specimens

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 2 hours from receipt in performing lab

Reference Values

Reference Interval: 

RANDOM  
< 3 days: 50-110 mg/dL
≥ 3 days: 70-199 mg/dL                                                                                   

 

FASTING  
< 3 days: 50-99 mg/dL
≥ 3 days: 70-99 mg/dL                                                                                   

Critical Value: (fasting and random)

<3 days: <45 mg/dL OR >or= 450 mg/dL
≥ 3 days: <55 mg/dL OR >or= 450 mg/dL

Critical results will be called back automatically initially and every 24 hours thereafter.

 

Methodology

UV (Enzymatic reference method with hexokinase)

Limitations

  • In very rare cases gammopathy, in particular type IgM (Waldenstrom's macroglobulinemia) may cause unreliable results.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: Centrifuge to separate within 2 hours of collection. If specimen is collected in microtainer or plain red-top tube aliquot sample into a Roche false-bottom tube for testing (labeling aliquot with specimen type).

Processed Volume: 0.3 mL plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 2 hours (12 hours if in Sodium Fluoride tube) 
Plasma/Serum (processed) Refrigerated (preferred) 3 days
  Ambient  24 hours
  Frozen  1 year

Test Classification and CPT Code

82947

LOINC

2345-7

Last Reviewed

06/2025