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Hepatic Cytochrome P450 Enzyme Activity Profile (Specific Substrate Metabolism)

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

This test measures how well your liver breaks down certain medications or chemicals, using a specific natural substrate. It helps assess liver function and drug metabolism efficiency.

Quick summary

["Evaluates liver’s ability to process medications and chemicals safely."]

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

Key facts at a glance

LOINC
49603-4
Short code
HCV RNA CSF NAA+probe-Log IU
Synonyms
HCV RNA CSF NAA+probe-Log IU
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
86803
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What This Test Measures

The test evaluates the activity of specific enzymes in the liver that metabolize a particular substrate, often used to monitor how efficiently your liver processes drugs or toxins. This can help identify potential issues with drug interactions or liver impairment.

Why It’s Ordered

Your healthcare provider may order this test if you’re taking medications that rely on liver metabolism, if you have symptoms suggesting liver problems (e.g., fatigue, jaundice), or if you’re undergoing treatment requiring precise drug monitoring.

Common Uses in Clinical Practice

This test is particularly useful for patients on medications like certain antidepressants, antipsychotics, or anti-seizure drugs, where liver metabolism plays a critical role in effectiveness and safety. It can also help guide dosing adjustments.

Sample Collection and Preparation

A blood sample is typically collected from a vein in your arm. The sample is processed to isolate the relevant enzymes, and the substrate is added to measure how quickly it’s broken down by these enzymes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Liver enzyme function test (substrate metabolism)

Frequently asked questions

How does this test differ from a general liver function test?
Unlike standard liver function tests (e.g., ALT, AST, bilirubin), this test focuses on a single enzyme’s activity using a specific substrate. It provides targeted insight into drug metabolism pathways, which may not be captured by broader liver function panels.
What if my results show abnormal enzyme activity?
Abnormal results may indicate liver dysfunction, genetic variations affecting metabolism, or interactions with certain medications. Your provider will discuss next steps, which could include adjusting medications or further testing.
Can this test be done at home?
No, this test requires a lab sample collected by a healthcare professional. Results are typically reported within a few days, depending on lab processing times.
  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