Glucose Tolerance, Standard (Non-Pregnant) Fasting, 1 Hour and 2 Hour (75g)


Abbrev Code:GTTF   
Order Code:LAB1170Order Name:Non-Gestational Glucose Tolerance Testing 2 Hour
Order Instructions:Order test panel; after collection of each specimen, the subsequent specimen will be generated in the patient's chart and can be brought into the collection activity at the time interval.
Synonyms:GTT2; Oral Glucose Tolerance Test (OGTT)
Methodology:Bichromatic end point; glucose oxidase
CPT Codes: 82947 x1, 82950 x1
Test Includes:Fasting and 120 min glucose. Fasting: GTTF, LAB1170, PLAB1170; 2 Hour: GTT2, LAB1172, PLAB1172. Adult dose is 75 g glucose. Pediatric dose is 1.75 g glucose/kg of body weight up a maximum dose of 75 g. For pregnancy, refer to Glucose Tolerance, Std. Gestational
Turnaround Time:Performed Mon-Fri, 0700-1700; turnaround time is 2 hours from the time the last specimen was collected.
Special Instructions:The oral glucose tolerance test (OGTT) is not recommended for routine clinical use.


Collection Instructions

Specimen:Blood
Optimal Volume:2.5 mL
Minimum\Peds Volume:0.6 mL
Container:Green (lithium heparin, gel), St Johns/St Joseph/Woodwinds - Gray Na Fluoride)
Alternate Containers: Green (lithium heparin, no gel), Red (no gel), Red or gold (gel), St Johns/St Joseph/Woodwinds-Green (lithium heparin, no gel), St Johns/St Joseph/Woodwinds - Red (no gel), St Johns/St Joseph/Woodwinds - Purple (EDTA)
Collection Instructions:Glucose Tolerance Protocol  
  • Measure fasting urine or blood glucose level before glucose solution is administered. Abnormal fasting results greater than 126 mg/dL are reported to the physician before continuing the test,
  • Administer oral glucose solution and begin timing as patient finishes the glucose solution. Adult loading dosage is 75 g glucose by mouth in at least 300 mL fluid. Pediatric dose is 1.75 g glucose/kg body weight, not to exceed 75 g.
  • Collect specimens 2 hours from the time the patient finishes the glucose solution. Occasionally a 1 hour specimen is collected.  Label each specimen with collection time, patient name and identification number.
  • For glucose tolerance blood specimens collected in hospital, deliver to laboratory individually as collected. Should not perform on hospitalized patients in a stressed state.
Patient Preparation:Please do not eat 10-12 hours before your appointment if you are coming in fasting for labs on lipids, cholesterol or glucose (sugar). This does not apply to pregnant women.
Water, hot tea and black coffee (with nothing added) is okay. Do not drink other fluids, diet soda or chew gum.
If you have concerns about taking your medications, please send a message by clicking on Secure Messaging, Message Your Care Team.
Contraindications:If patient becomes ill or vomits, test must be discontinued.


Processing and Shipping

Specimen Processing:Centrifuge and aliquot 1.25 mL, 0.2 mL minimum for each timed specimen collection. Store in refrigerator.
Shipping Instructions:Ship at refrigerated temperature.
Stability:Once separated from cells, Room temperature - 8 hours; refrigerated - 72 hours.
Test Performed at or Referral Lab Chemistry  (M Health Maple Grove Clinic, Range, UMMC-East Bank, Oxboro Bloom, Lakes, Ridges, Northland, Southdale, UMMC/UMMCH-West Bank, Clinics, M Health Clinic and Surgery Center, Grand Itasca, St. Joseph's, St. John's, Woodwinds)


Interpretive

Reference Range:Glucose Tolerance Reference Ranges


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