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Test Code GTT P2H Glucose Tolerance 2 Hr

Important Note

When administered by Seattle Children's lab at the main campus, this test must be scheduled with the Chemistry Laboratory 206 987-3860.  Outside orders should be faxed to 206 985-3124.

When administered by Seattle Children's lab at the regional clinic locations, this test must be scheduled by emailing:

  • Bellevue Clinic Lab: BellevueLabAssistants@seattlechildrens.org

  • South Clinic Lab: SouthClinicLabAssistants@seattlechildrens.org

  • North Clinic Lab: NorthClinicLabAssistants@seattlechildrens.org

 

If administering in Infusion Clinic, order in EPIC and send samples to main campus for testing.

Clinical System Name

Glucose Tolerance 2 Hr - 2 Tests

Synonyms

Modified OGTT

Description

Test must be pre-scheduled.

To schedule this test at main campus, call Chemistry Laboratory (206) 987-3860.

To schedule this test at regional clinics, email the regional lab: 

  • Bellevue Clinic Lab: BellevueLabAssistants@seattlechildrens.org

  • South Clinic Lab: SouthClinicLabAssistants@seattlechildrens.org

  • North Clinic Lab: NorthClinicLabAssistants@seattlechildrens.org

Test includes STAT fasting glucose and a glucose 2 hr post Glucose load.  Glucose drink is given to the patient only after fasting glucose result is completed by laboratory technologist.  If fasting result is <126 mg/dL, laboratory technologist will administer glucose drink.

Sample Requirements

Specimen: Whole Blood

Container(s): Lt. Green/Lithium Heparin Microtainer, Dark Green/Sodium Heparin,

Preferred Vol: 1 mL

Minimum Vol: 0.5 mL 

Notes:  Main campus: call Chemistry when patient arrives for appointment (7-3860). Use microtainer collection for fastest turnaround time. 

 

 

Processing Instructions

Reject due to: Age of specimen, hemolysis, line contamination

Spin: Y

Aliquot: Y

Temp: 2-8oC

Storage location: Fasting glucose performed by chemistry tech on EPOC or regional tech on Vitros. Main lab: deliver 2 hr sample to Core.

Off-site collection: Call Chemistry Laboratory ((206) 987-3860) or email regional laboratory to schedule test. Test must be collected at Seattle Children's.

Stability

 

Specimen Type Temperature Time
whole blood RT 30 m
Plasma RT

≤ 24 H
Plasma 2-8oC

≤ 7 D
Plasma -20oC or -70oC

≤ 365 D

Note:  metabolism of glucose by the cells is approximately 7% per hour at room temp. 

Availability

STAT Performed TAT
N M - F, day shift 1 d

 

Performing Laboratory

Seattle Children's Laboratory    

Department

Department:  Chemistry, Regional Labs

Location: Chem East, Regional Labs

Phone Number: 206-987-3860

 

Methodology

Method: Amperometric by Epoc (fasting sample); Colorimetric method by Vitros or Rapidpoint 405 (2 H sample)

Analytical Volume:     Epoc 0.1 mL whole blood

                                     Vitros: 0.02 mL + 0.03 mL dead space

                                     Rapidpoint 405: 0.20 mL

Limitations: Method is affected by line contamination and hemolysis. Not affected by sodium fluoride.

 

Reference Range

 

FASTING GLUCOSE (mg/dL)   2 HOUR POST GLUCOSE (mg/dL)  
< 110  Normal < 140  Normal
≥ 110  and < 126 Impaired ≥ 140 and < 200  Impaired
≥ 126  Diabetes ≥ 200  Diabetes

 

CPT Codes

82947

82950