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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Lidocaine

Test Code(s): LIDO / HCLIDO

CPT Code(s): 80176

Test Description: Test Component:

Lidocaine and monoethylglycinexylidide (MEGX)

Methodology: Gas Chromatography

Clinical Significance: Antiarrhythmic, local anesthetic

Days Performed: Daily, dayshift- Pathology Resident approval is required after hours.

Turnaround Time: Stat: 3 hours.
Routine: 24 hours.

Specimen Requirements

Specimen: Blood

Collection Instructions: Collect specimen:
1) if lidocaine toxicity is suspected
2) whenever ventricular dysrhythmias occur despite        
     lidocaine administration.

Collection Container: Preferred: Red top

Collection Volume: Preferred: 4 mL
Pediatrics: 3 mL

Sample Analyzed: Serum

Volume Required: Preferred: 2 mL
Pediatrics: 1 mL

Specimen Processing: Centrifuge. Transfer cell-free serum to plastic vial. Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Unacceptable Criteria: Specimens collected in red cap with yellow ring (SST) tubes are not acceptable.

Stability: Ambient: 14 days
Refrigerated: 14 days
Frozen: 6 months


Interpretive Guidelines:
Generally effective therapeutic concentration:  
18 years and up:  Lidocaine 2.0-5.0 mcg/mL  
  MEGX 0.5-2.0 mcg/mL  
18 years and up:  Lidocaine >6 mcg/mL  
  MEGX >6 mcg/mL  


Critical Calls: View

Additional Information:

Result of "BELOW" indicates that the result is below method detection limit of 0.1 mcg/mL. The half-life is approximately 1-2 hours. Lidocaine is metabolized to monoethylglycine-xylidine (MEGX).


This test was developed and its performance characteristics determined by the UWHC Clinical Laboratories.  This test meets the standards for clinical testing.  This test should not be regarded as investigational or for research use.  The US Food and Drug Administration (FDA) has not approved or cleared this test; however, the FDA has determined that such clearance or approval is not necessary.


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