- Start Date
- Expiration Date
- CPT Codes
- Reference Test
- Transport Info
If specimen not sent to SBMF on day collected:
– Serum sample tubes, clot 30 minutes
– Promptly centrifuge 15 minutes
– Immediately transfer serum or plasma to separate plastic tube
- Fasting Required?
- Patient Instructions
- Reference Range
Enzyme Multiplied Immunoassay Technique (EMIT)
Therapeutic drug monitoring; evaluate toxicity.
Lidocaine, administered intravenously, is a drug effective in the treatment of ventricular arrhythmias. It is also widely used as a local anesthetic where significant systemic absorption can occur. Lidocaine therapeutic effectiveness and toxic side effects show a consistent relationship to the blood concentration rather than the administered dosage. Because of the short half-life and the unpredictability of blood concentrations in patients suffering from cardiac or liver disease, lidocaine should be measured in patients as soon as possible after the blood sample is drawn.Peak serum levels of lidocaine in the range of 1.5 to 5 µg/mL are suggested for optimal therapeutic effectiveness. Elevated concentrations of lidocaine (10 µg/mL) may produce dizziness, tinnitus, drowsiness, paresthesias, twitching, hypotension, bradycardia and double vision. Convulsions and cardiac and respiratory arrest may occur. The metabolism and elimination may be altered by disease states. Patients in cardiac failure under long-term infusions may produce 50% greater plasma concentrations often resulting in central nervous system depression. Patients with chronic liver disease can have reduced lidocaine clearance and may develop toxicity with normal dosage regimens. Prophylactic administration of lidocaine is reported to produce instances of toxicity resulting in symptoms such as dizziness and nausea, to coma or seizures.