Specimen Requirements

Collection Instructions:

1. Serum and Plasma gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.

Submit only 1 of the following specimens:

Preferred:

Serum

Draw blood in a gold-top serum gel tube(s). Spin down and send 1 mL of serum refrigerated. Pre-dose specimen is recommended.

Note:  1. Patients receiving fosphenytoin should be drawn at least 2 hours after an intravenous dose and 4 hours after an intramuscular administration to prevent cross reactivity.

2. Date and time of draw is required on request form and specimen for processing.

3. A speckled-top serum gel tube (s) or a plain, red-top tube(s) is also acceptable.

4. Indicate serum on request form.
5. Label specimen appropriately (serum).

Alternate:

Plasma

Draw blood in a mint green-top (heparin) gel tube(s). Spin down and send 1 mL of heparinized plasma refrigerated. Pre-dose specimen is recommended.

Note:  1. Patients receiving fosphenytoin should be drawn at least 2 hours after an intravenous dose and 4 hours after an intramuscular administration to prevent crossreactivity.

2. Date and time of draw is required on request form and specimen for processing.

3. Indicate plasma on request form.

4. Label specimen appropriately (plasma).

Sample Stability Information:

Stable 7 days refrigerated