Glucose, gestational diabetes screen (GDS)

Back to List

Test Name:

Glucose, gestational diabetes screen (GDS)

Testing Prerequisites:

EDMONTON/CENTRAL/NORTH ZONES:
• Patients and physicians:
A 4-hour fast may be beneficial, but is not required
• The number of patients with a normal follow up tolerance testing can be
reduced if patients do not eat immediately prior to the gestational diabetes
screen
• Some patients who do not fast will have a positive gestational diabetes screen
but the follow up tolerance testing will be negative

• Patient Care Centre Staff:
• Accommodate fasting and non-fasting patients
• Gestational diabetes screen can still be performed if a patient is not fasting

CALGARY/SOUTH ZONE:
• Fasting is not required

Patient Instructions:

Gestational Diabetes Screen pre-testing instructions

Collection Device/Tube Type:

1. EDM Base Lab: 5 mL blood - GOLD SST (gel)
2. CGY DSC: 4.5 mL blood - MINT LIHEP PST (gel)
3. NOTE: The preferred tube type at each testing site is acceptable at the alternate site

Collection Instructions:

This test cannot be collected by Mobile Collection Service

• Administer a 50 g glucose load
• Draw a blood sample at 1 hour

Submission Requirements:

1 mL serum or lithium heparin

Frequency of Testing:

Daily

Reference Range:

For clinical interpretation, see Canadian Diabetes Association Clinical Practice Guidelines

Critical Values:

Less than 2.6 mmol/L or greater than 24.9 mmol/L

Comments:

Guidelines suggest testing between 24th and 28th week of gestation. Test should not be performed at or after 35 weeks of gestation. Fasting blood glucose and/or Hemoglobin A1c (HbA1c) are the recommended tests at or after 35 weeks gestation.

Last Reviewed:

05 May 2023

Back to List