Specimen Requirements

Serum or plasma should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.

• Draw blood in a green-top (lithium heparin) tube(s) or a red-top tube (serum) following an 8 to 12 hour fast.
• After fasting specimen is drawn, give lactose dose of 100 g:  two 50 g containers dissolved in 250 mL of water. Ingestion should be completed within 10 minutes. The timing starts at this point.
• Draw blood in a green-top (lithium heparin) tube(s) or a red-top tube (serum) at 30 minutes, 1 hour, 2 hours, and 3 hours after ingestion of dose. 
• Patient must not eat or drink during the time of collection, with the exception of plain water.
• They may be given a limited amount of ice chips or plain water to moisten mouth.
• Spin down each specimen, separate plasma or serum from cells as soon as possible after each draw, and send 1 mL of heparinized plasma or serum for each timed (fasting, 30 minutes, 1 hour, 2 hours, and 3 hours) interval,
• Vomiting negates test.
• Label each specimen appropriately (each timed interval).