Test Name

Dilantin (Phenytoin)

Specimen Type & Acceptability

Serum – Red top tube only – 2 days refrigerated. SST tubes will be rejected.

General Use

Used in the diagnosis and treatment of phenytoin overdose and in monitoring levels of phenytoin to ensure appropriate therapy.

CPT Code(s)


Special Instructions

Collect using a BD red top tube with NO gel and NO additives. Let clot for 10-20 minutes. After the sample is fully clotted, centrifuge the sample. Verify complete separation of cells and serum. Transfer serum to aliquot tube, label tube with two unique identifiers and serum obtained from red top tube. Refrigerate Immediately.

Container/Tube Type


1 mL Min. vol. = 100 ul

Suggested Tube Types


Typical Volume

Gold Top Serum Separator Tube (SST)

⋜ 5 mL

Tiger Top Serum Separator Tube (SST)
^For larger volume tests

> 5 mL

Red Top Tube (No additive)

⋜ 5 mL

EDTA Whole Blood

3 mL

3.2 % Sodium Citrate Whole Blood

2.7 mL

Lithium Heparin Plasma Separator Tube

⋜ 5 mL