Serum/plasma concentration of free indocyanine green (ICG)
This test measures the amount of a dye called indocyanine green that your body can clear from the bloodstream. It helps assess liver function, particularly how well your liver processes and removes substances from circulation.
["A test for liver function that tracks how efficiently your liver clears a dye from your blood."]
Key facts at a glance
- LOINC
- 96490-8
- Short code
- NIF IgG CSF Ql IF
- Synonyms
- NIF IgG CSF Ql IF
- Category
- chemistry
- Sample
- csf
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- if
- CPT
- 82784
- Specimen volume
- 1-2 mL
- Stability
- Immediate analysis required, Refrigerated: 1h
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
What Is Free Indocyanine Green (ICG) Used For?
Free ICG is primarily used to evaluate liver function, especially in diagnosing conditions like cirrhosis, bile duct blockages, or severe liver disease. It can also help determine the effectiveness of liver transplants or treatments for liver-related disorders.
How Is the Test Performed?
A small amount of indocyanine green dye is injected into a vein. Your blood is then tested at specific time points to measure how quickly the dye is cleared from your bloodstream. This process is usually done in a hospital or clinic setting with medical supervision.
Why Might You Need This Test?
Your doctor may recommend this test if you have symptoms of liver problems, such as jaundice (yellowing of the skin or eyes), fatigue, or unexplained weight loss. It may also be used before liver surgery, to monitor liver transplant patients, or to assess liver function in people with chronic liver diseases.
What Are the Possible Results?
A higher than expected level of free ICG in your blood suggests your liver is not working as well as it should, which could indicate liver damage or disease. Lower levels may suggest normal liver function or improved liver health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated ICG levels often point to reduced liver function, which can be caused by chronic liver diseases, cirrhosis, or other conditions that impair bile flow. This test is particularly useful in diagnosing and monitoring conditions that affect how well the liver processes and removes toxins from the blood.
Short name
Free ICG Level
Frequently asked questions
What does an abnormal ICG result mean?
How long does it take to get results from this test?
Is there any preparation needed before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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