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Lysine concentration in serum or plasma

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

This test measures the amount of lysine, an essential amino acid, found in your blood.

Quick summary

["Lysine helps your body build proteins and maintain healthy cells."]

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

Key facts at a glance

LOINC
47692-9
Short code
Lysine SFr Amn
Synonyms
Lysine SFr Amn
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Lysine Does in Your Body

Lysine plays a key role in protein synthesis, immune function, and calcium absorption. It’s also involved in the production of certain hormones and neurotransmitters. While lysine is naturally present in foods like meat, dairy, and legumes, your body also produces some through metabolism.

Why Your Doctor Might Order This Test

Doctors may check lysine levels if you have conditions like kidney disease, certain infections, or metabolic disorders. It can also be part of broader tests to assess protein metabolism or nutritional status.

How the Test Works

A small blood sample is taken, usually from your arm. The sample is then analyzed to measure lysine concentration using a specialized laboratory technique, often an immunoassay or enzymatic method.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if instructed by your doctor. Wear comfortable clothing and plan to stay for the blood draw.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Lysine Level

Frequently asked questions

What does an abnormal lysine level mean?
Low lysine levels may indicate kidney problems, malnutrition, or certain metabolic disorders. High levels could suggest liver disease, overproduction of certain compounds, or rare genetic conditions. Your doctor will interpret results in the context of your overall health and symptoms.
How often should I get this test?
This test is typically ordered as needed for diagnostic purposes or monitoring specific conditions. Your doctor will determine the frequency based on your health status and treatment plan.
Can I eat or drink before the test?
Follow your doctor’s instructions, but generally, avoid food for 8–12 hours before the test if fasting is required. Water is usually allowed unless specified otherwise.
  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