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Lidocaine Concentration (Serum or Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of lidocaine, a medication used to numb areas of the body or prevent pain during procedures, in your blood.

Quick summary

["Knowing your lidocaine levels helps doctors monitor how your body is responding to this medication."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
73305-5
Short code
Lidocain ind plt IgG SerPl Ql FC
Synonyms
Lidocain ind plt IgG SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order a lidocaine level test if you’re receiving this medication for procedures like dental work, heart rhythm monitoring, or pain management. It helps ensure safe dosing and prevents side effects like dizziness, nausea, or heart rhythm changes.

What to Expect Before the Test

You’ll typically have a small needle inserted into your arm or vein to draw blood. The process is quick and usually painless. If you’re on lidocaine for a procedure, your blood sample may be taken before, during, or after the treatment.

What the Results Mean

Results show how much lidocaine is in your blood at the time of testing. High levels may indicate overdose risk, while low levels could mean the medication isn’t working as intended. Your doctor will interpret these results in the context of your treatment plan.

Common Side Effects and Risks

Lidocaine is generally safe when used properly, but high blood levels can cause dizziness, confusion, or irregular heartbeat. Rarely, it may affect heart function or cause allergic reactions. Always follow your doctor’s instructions for dosing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Lidocaine Level

Frequently asked questions

What causes a lidocaine level test to be ordered?
A lidocaine level test is ordered when a healthcare provider prescribes lidocaine for medical procedures, pain management, or cardiac monitoring. It helps ensure safe dosing, especially in patients with liver issues (since lidocaine is metabolized by the liver) or heart conditions.
How often should I get this test?
The frequency depends on your treatment plan. Your doctor may order it before, during, or after procedures, or periodically if you’re on long-term lidocaine therapy. Follow your healthcare provider’s recommendations.
Can I eat or drink before this test?
You can usually eat and drink normally unless your doctor specifies otherwise. Some tests may require fasting, but lidocaine level tests do not. Always check with your provider before preparing for the test.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy