Test Entry - Detail

Glucose Tolerance Test with Insulins

General

Clinical Use:

A GTT with insulin measured at each time point. Used for the investigation of insulin resistance in a research setting.
Suggest a fasting insulin with glucose only, for routine patient assessment.

Availability:

Samples are tested routinely during the testing laboratory's hours of operation.

Aliases/Synonyms:

GTT with Insulins, Insulins with GTT, OGTT with Insulins, Oral Glucose Tolerance Test with Insulins,

Code:

ING

Handling Instructions (to laboratory):

Send samples chilled.

Hyperlink:

Reference Interval:

Fasting Insulin reference interval: <12 mU/L







Diagnostic Criteria 75g GTT (mmol/L)



Fasting
2 hour


Normal
<=6.0 and
<7.8


Impaired
6.1-6.9 and/or
7.8-11.0


DM
>=7.0 and/or
>=11.1


Diagnostic Criteria 75g GTT in Pregnancy ADIPS 2025 (mmol/L)



Fasting
1 hour
2 hour


Normal
<5.3 and
<10.6 and
<9.0


Gestational DM
5.3-6.9 or
>=10.6 or
9.0-11.0


Overt DIP
>=7.0 or

>=11.1

Collection Requirements

Container:

Fluoride Oxalate (GREY), and, Serum Sep. Tube-SST (GOLD),

Sample Type:

See container

Minimum Collection Volume:

1mL

Collection Instructions:

Patient must be fasting.
Samples for glucose AND insulin should be collected at baseline, 1 hour and 2 hours after glucose load.
GTT Procedure Slip

Processing Requirements

Alternate Containers:

Processing Instructions:

Minimum Assay Volume:

200uL

Stability:

Transport Instructions (to testing laboratory):

Send samples chilled.

Testing Locations

Performed at:

Section	Department	Site	Contact Phone
Core	Biochemistry	Fiona Stanley Hospital	6152 8140
Core	Biochemistry	QEII Medical Centre	6383 4093

Last Updated : 29-08-2025 14:01