Specimen Requirements

Consult physician for specific orders. Patient should be instructed to eat and drink nothing except water for 10 to 14 hours prior to test. Patient should be instructed to refrain from smoking and drinking coffee just before and during test.

Specimen Type: Plasma

Container/Tube: Green top (lithium heparin gel)

Specimen Volume: 1 mL for each timed interval

Collection Instructions:

1. Draw blood specimen for a fasting glucose. Do not perform test if patient is not fasting or fasting glucose is >120 mg/dL.
2. Give patient standard glucose solution:
A. 75 g challenge for 2-, 3-, 4-, and 5-hour non-pregnant adults
B. 100 g challenge for 3-, 4-, and 5-hour pregnant females
C. 50 g challenge for 1-hour antepartum screen
3. Have patient remain quiet for duration of test.
4. Start timing when patient finishes glucose solution.

5. Draw blood specimens at the following intervals: 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours or per physician’s order.

6. Label specimens appropriately (corresponding draw times and intervals). 

7. Spin down within 45 minutes of draw. Avoid prolonged contact of plasma with separated red cells; or hemolyzed, icteric, or lipemic specimen.