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Test Code LID / LID-M Lidocaine, Serum

Additional Codes

Software                    Test Code                    
SoftID                                       LID                                                  
EPIC LAB20635
Mayo LID

Reporting Name

Lidocaine, S

Useful For

Assessing optimal lidocaine dosing during the acute management of ventricular arrhythmias following myocardial infarction or during cardiac manipulation such as surgery

 

Assessing potential lidocaine toxicity

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum Red


Specimen Required


Supplies: Sarstedt Aliquot Tube 5 mL (T914)

Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 14 days
  Ambient  14 days
  Frozen  14 days

Reference Values

Therapeutic: 1.5-5.0 mcg/mL

Critical value: >6.0 mcg/mL

Day(s) Performed

Monday through Saturday

Report Available

Same day/1 to 2 days
NorDx Test Catalog Note:

Analytic time for send out tests is the time it will take to perform testing once it has arrived at the performing reference lab. Please add 1 to 2 days from time of collection to allow for receipt at NorDx central lab and shipment of specimen, add another day if specimen is collected on the day before a weekend or holiday.

Secondary ID

8382

Method Name

Enzyme-Multiplied Immunoassay Technique (EMIT)

Reject Due To

Gross hemolysis Reject

Clinical Information

Lidocaine is commonly used as a local anesthetic, but it is also effective at controlling ventricular arrhythmia and ventricular fibrillation in children and adults. For cardiac therapy, optimal therapeutic response is seen when serum concentrations are between 1.5 and 5.0 mcg/mL. Lidocaine is protein-bound (60-80%), primarily to alpha-1-acid glycoprotein; concentrations of this protein increase after myocardial infarction, which may decrease the amount of free lidocaine and, thus, its efficacy.

 

Lidocaine undergoes extensive first-pass hepatic metabolism and, therefore, is not administered orally. It is eliminated via renal clearance, with a half-life of approximately 1.5 to 2 hours. Diseases that reduce hepatic or renal function reduce clearance and prolong elimination of lidocaine.

 

Toxicity occurs when the serum concentration of lidocaine is greater than 6.0 mcg/mL and is usually associated with symptoms of central nervous system excitation, light-headedness, confusion, dizziness, tinnitus, and blurred or double vision. This can be accompanied by bradycardia and hypotension leading to cardiovascular collapse.

Cautions

No significant cautionary statements

Method Description

The enzyme-multiplied immunoassay technique assay is a homogeneous enzyme immunoassay technique used for the analysis of specific compounds in biological fluids. The assay is based on competition between drug in the sample and drug labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PD) for antibody binding sites. Enzyme activity decreases upon binding to the antibody, so the drug concentration in the sample can be measured in terms of enzyme activity. Active enzyme converts oxidized nicotinamide adenine dinucleotide (NAD) to NADH, resulting in an absorbance change, which is measured spectrophotometrically. Endogenous serum G6PD does not interfere because the coenzyme functions only with the bacterial (Leuconostoc mesenteroides) enzyme employed in the assay.(Package insert: Lidocaine reagent. Seimens Healthcare Diagnostics, Ltd; 04/2015)

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80176

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LID Lidocaine, S 3714-3

 

Result ID Test Result Name Result LOINC Value
8382 Lidocaine, S 3714-3

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.