Specimen Requirements

Patient Preparation

1. Patient is not required to be fasting.

2. Consult physician for specific orders.

3. Patient should discontinue medication 3 days prior to test, if possible.

4. Patient should be on at least a 150 g carbohydrate diet for 3 days prior to test.

5. Patient should be instructed that smoking and mild exercise are not permitted.

6. This test should not be performed on those patients who have had an illness during the prior 2             weeks.

7. Drugs such as salicylate, diuretics, and anticonvulsants should be avoided at least 3 days prior to        performance of test.

8. It is preferred for patient to stay in the unit until specimens have been drawn.

Performance of Test

1. Give patient standard glucose solution, 50 g for adults.

2. Have patient remain quiet for duration of test.

3. Start timing when patient begins to drink glucose solution. Patient must consume glucose solution within 5 minutes.

4. Draw blood specimen(s) at 1-hour post ingestion.

Specimen Collection

Submit only 1 of the following specimens:

Preferred
Plasma:
Draw blood in a green-top (lithium heparin) tube. Spin down and send 1 mL of lithium heparin plasma refrigerated. Label the specimen with the patient’s name (first and last), date of birth, date and time of draw, phlebotomist’s initials, and as plasma. Hemolyzed or lipemic specimens are not acceptable.

Alternate
Serum:
Draw blood in a serum gel tube(s). Spin down and send 1 mL of serum refrigerated. Label the specimen with the patient’s name (first and last), date of birth, date and time of draw, phlebotomist’s initials, and as serum. Hemolyzed or lipemic specimens are not acceptable.

Note:  Glucose will drop 5.0 mg/dL to 10 mg/dL per hour in an unseparated, ambient serum gel tube.

Specimen stability:   8 hours at room temperature when spun
                                  3 days at 2-8°C
                                  ≥-20°C for longer storage
Minimum volume:  1 mL