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Test Code GTT P2H Glucose Tolerance 2 Hr

Important Note

This test must be scheduled with the Chemistry Laboratory 206 987-3860.  Outside orders should be faxed to 206 985-3124.

Clinical System Name

Glucose Tolerance 2 Hr - 2 Tests


Modified OGTT


Call Chemistry Laboratory to schedule the test (206) 987-3860.  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 Chemistry technologist.  If fasting result is <126 mg/dL, Chemistry technologist will administer glucose drink.

Sample Requirements

Specimen: Whole Blood

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


Preferred Vol: 1 mL

Minimum Vol: 0.5 mL 


Notes:  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. Deliver 2 hr sample to Core.


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



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. 


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


Performing Laboratory

Seattle Children's Laboratory    


Department:  Chemistry

Location: Chem East

Phone Number: 206-987-3860


Reference Range


< 110  Normal < 140  Normal
≥ 110  and < 126 Impaired ≥ 140 and < 200  Impaired
≥ 126  Diabetes ≥ 200  Diabetes



Method: Amperometric by epoc (fasting sample) Colorimetric method by Vitros 4600 or Rapidpoint 405 (2 H sample)

Analytical Volume:     Epoc 0.1 mL whole blood

                                     Vitros 4600: 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.


CPT Codes