Specimen Requirements

Patient Preparation:Patient should be fasting (8-14 hour).

Performance of Test:

1. Draw blood for a fasting glucose level.

Note:  1. If result is abnormal (<60 mg/dL or >99 mg/dL), cancel test and inform ordering physician.

2. If result is normal (60-99 mg/dL), continue as follows:

2. Obtain 100 g of glucose solution.

3. If patient is <100 pounds, a smaller dose of glucose solution should be calculated by the laboratory.

4. Have patient consume glucose solution within 5 minutes.

5. Start timing from first sip.

6. Draw specimen at 1-, 2-, and 3-hours post glucose solution ingestion.

Note:  If patient cannot completely consume glucose solution (or cannot keep it down) or drinks part of the glucose solution and spills the rest, the test must be cancelled and rescheduled.

Specimen Collection:

Submit only 1 of the following specimens:
 
Plasma
Draw blood in a green-top (lithium heparin) plasma gel tube(s). Spin down and send 1 mL of lithium heparin plasma refrigerated.
Note:  1. Indicate time of draw and plasma on request form.
2. Label specimen appropriately (time of draw and plasma).
 
Serum
Draw blood in a serum gel tube(s). Spin down and send 1 mL of serum refrigerated.
Note:  1. Indicate time of draw and serum on request form.
2. Label specimen appropriately (time of draw and serum).

Unspun specimens must be transported at ambient temperature and arrive to the laboratory within one hour of draw.