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Glucose Tolerance Test, 75 g
Alternative Names/Synonyms
2-hour OGTT, OGTT, Oral Glucose Tolerance Test
Laboratory
Core Laboratory & Transfusion Medicine
Sub-section
Biochemistry
Specimen Type
Blood
Test Code
GTTP2
Ordering Instructions, Requisition
This test is by
appointment only
.
Clinical Significance (If applicable)
Screening and diagnosing gestational diabetes mellitus (GDM).
Specimen Requirements (Sample Type)
Plasma
Specimen Requirements (Volume (mL))
0.5 mL
Specimen Requirements (Tube Type)
Plasma (Grey Tube)
Collection Containers – Tube Types
Collection Requirements
Collection Instructions
Sample Stability
Room Temperature: 3 days
Cause for Rejection
Specimen Acceptability and Transport Guidance
Instrument, Methodology
Roche cobas c 702, enzymatic
References
1.
https://guidelines.diabetes.ca/cpg/chapter36
Test Availability
Weekdays
Routine Turnaround Time
3 hours
Reference Ranges
A diagnosis of GDM is confirmed with one or more of the following glucose results:
Fasting > 5.3 mmol/L
1 hour > 10.6 mmol/L
2 hour > 9.0 mmol/L
In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.
Laboratory Contact Information
416-586-4800 extension 8070
Patient Preparation
Patient
must be fasting
for at least 8 hours prior to testing.
Ordering Practices
This should only be performed subsequent to a
Glucose Challenge Test, 50 g
between 7.8 - 11.0 mmol/L.
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