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Glucose, Tolerance Test, Gestational 3 Hour

Additional Codes

Atlas

Test Code Test Name
GTT3GEST Glucose Tol 3 Hour Gestational

 

Cerner:

Test Code Test Name
N/A GTT 3 Hr Gestational

Specimen Requirements

Patient Preparation

A fasting specimen is drawn.  Patient to be given 100g  glucose, or 100g of Fresh Test.  Fresh Test is an alternative to glucola and is provided by the patient. NOTE:  It is also acceptable to have the patient consume another source of glucose (jellybeans, sugar water, etc) if directed to by their provider

 

Blood to be drawn every hour for next three hours. 

 

Instruct patient to remain fasting (no food, no drinks, only sips of water) throughout the test.  Advise no smoking and limited exercise.  Advise patient to inform lab or nursing staff when symptoms of nausea, vomiting, dizziness, dyspnea, fainting occur.

 

Container Type: 

Gold Top 6mL SST Gel & Clot Activator Tube

Or

 

Green Top 5mL Lithium Heparin Separator Tube

Or

 

5.5mL Sodium Fluoride(NaF)/Potassium Oxalate Grey Top Tube

Specimen Type:

Serum or Plasma

 

Specimen Volume: 

2.5 mL Serum or Plasma

minimum .5 mL of Serum or Plasma

 

Specimen Handling/Transport:

Separate serum or plasma  from cells within 2 hours of collection if not in NaF (grey top).  Transport ambient room temperature.

 

Specimen Stability/Storage:

8 hours ambient room temperature or 24 hours ambient room temperature if NaF (grey top)

3 days refrigerated 2-8°C

 

Performing Laboratory

Munson Healthcare Laboratories

Priority, Frequency, & Turnaround

Priority:

Non-Emergent

 

Frequency:

Monday through Sunday

 

Turnaround:

0-1 Day

Methodology

Glucose Hexokinase

Reporting

Reference Range:

Fasting: 70-94 mg/dL

1-Hour: 70-179 mg/dL

2-Hour: 70-154 mg/dL

3-Hour: 70-139 mg/dL

 

Critical Decision:

Pediatric patients up to 21 years old  ≤ 35 mg/dL, ≥ 200 mg/dL 

Patients 21 years and older  ≤ 50mg/dL, ≥500 mg/dL

 

Note:  Critical values are called to the provider and communicated as critical.  Documentation of the call is recorded in the patient record.

Clinical Significance

Glucose is the major energy source for the human body.  Glucose determinations are ordered for the diagnosis and follow-up of abnormalities of carbohydrate metabolism.  This test is a definitive test for gestational diabetes.

CPT Code(s)

82951-Tolerance test (GTT), 3 specimens (includes glucose)

82952-GTT, each additional beyond 3 specimens