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Glucose Tolerance Test 2 Hr Diab Mellitus (75 gram)

Important Note

Patient must be fasting for 8 to 14 hours before initial blood draw.

Additional Codes

Epic# -

LAB5716

 

Cerner name(s):

  • GTT 75 gram 2hr non-gestational screen or Glucose Tolerance testing 75 gram 2hr non-gestational screen.

Performing Lab(s)

Memorial-Belleville & Memorial-Shiloh

Specimen Requirement (s)

Specimen Type: plasma (preferred) or serum

Container/Tube:   mint green LiHep tube, SST (gold or marble), plain red top, lavender (EDTA) tube

Specimen Volume:    full tube

Specimen Minimum Volume: 1 mL of plasma

 

Collection Instructions:

  1. Draw fasting specimen.
  2. Give patient 75 g glucose tolerance beverage (or acceptable substitute as determined by lab or physician)
  3. Draw 2nd specimen at 2 hours post consumption of beverage.

Unacceptable Conditions

Avoid hemolysis. 

Day(s)/Shift(s) Test Set Up and Turnaround Time

Sunday through Saturday

Hours: 24 hours

 

Turnaround Time:

STAT: No

Routine: less than 8 hours from receipt.

Transport and Stability

Transport temperature: Ambient to lab

Reference Values

Fasting (2H/75g)

Reference Values

Critical Low

Critical High

70 - 99 mg/dL

≤ 54 mg/dL

≥ 450 mg/dL

 

2 hours post (2H/75g)

Reference Values

Critical Low

Critical High

< 139 mg/dL

≤ 54 mg/dL

≥ 450 mg/dL

Interpretive Data

Interpretive Data:

Type 1/Type 2 Diabetes Non-Gestational Adults:

FASTING

Normal: 70-99 mg/dL

Impaired Glucose Tolerance: 100-125 mg/dL

Possible Diabetes: >125 mg/dL

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2-HOUR

Normal: 70-139 mg/dL

Impaired Glucose Tolerance: 140-199 mg/dL

Possible Diabetes: >199 mg/dL

Intermediate 2-hour value indicates impaired glucose tolerance, while intermediate fasting value indicates impaired fasting glucose.

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Reference Interval Info: Diabetes Care 2020; 43(Suppl 1):S14-31

Current interpretive data was last revised on 11/01/2020.