Specimen Requirements

Serum or plasma required. Draw blood in a plain, red-top tube(s), serum gel tube(s), heparin, EDTA or oxalate tube. Spin down and send 1 mL (pediatric:  0.2 mL) of serum.  

Store the specimen refrigerated at 2-8⁰C. Specimen is stable for 2 hours at 2-8⁰C^.  For transporting, maintain the sample temperature at 2-8⁰C.

Pharmacokinetics factors influence the correct time of sample collection after the las drug dose.  These factors include dosage form, mode of administration,concomitant drug therapy, and biological variations affecting drug disposition.

Sample collection time guidelines:

• 12 hours after initiating prophylactic lidocaine therapy after suspected myocardial infarction, and daily thereafter during lidocaine treatment
• at least every 12 hours in patients with evidence of cardiac or hepatic insufficiency
• whenever lidocaine toxicity is suspected
• whenever ventricular arrhythmias occur despite lidocaine administration