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Hepatic Cytochrome P450 Enzyme Activity (Specific Substrate Metabolism)

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

This test measures how well your liver’s enzymes break down certain medications or chemicals, which helps assess liver function and drug metabolism.

Quick summary

Evaluates liver’s ability to process medications and toxins safely.

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

Key facts at a glance

LOINC
49604-2
Short code
HCV RNA Mar NAA+probe-Log IU
Synonyms
HCV RNA Mar NAA+probe-Log IU
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
86803
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

What This Test Measures

Your liver contains enzymes called cytochrome P450 (CYP) that metabolize drugs, toxins, and other substances. This test evaluates the activity of specific CYP enzymes by measuring their ability to convert a known substrate into a detectable product. Results help doctors determine how efficiently your liver processes medications or environmental chemicals.

Why It’s Ordered

Doctors may order this test if you’re taking medications that rely on liver metabolism (e.g., blood thinners, antidepressants, or cancer treatments), have liver disease, or experience unexplained symptoms like fatigue, jaundice, or nausea. It also helps monitor drug interactions or toxicity.

Sample Collection and Preparation

A blood sample is taken from a vein in your arm. The test may use serum or plasma, depending on the specific substrate and method. No special preparation is needed, but avoid alcohol for 24 hours before testing to ensure accurate results.

What to Expect

The process is quick and painless. You’ll feel a small pinch when the needle is inserted, but most people tolerate it well. Results are typically available within a few days, depending on lab processing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Liver CYP Enzyme Function Test

Frequently asked questions

This test helps identify liver dysfunction, drug metabolism issues, or genetic variations in CYP enzymes that could affect how you respond to medications. Low enzyme activity may indicate liver disease, while high activity could suggest genetic differences or other metabolic conditions.
If your results are abnormal, your doctor may recommend further testing (e.g., liver function panels) or adjust your medication dosage to avoid toxicity or ineffectiveness.
How long does it take to get results?
Results are usually ready within 3–5 business days, but timing depends on your lab’s workflow. Your doctor will contact you once they’re available.
Can I drink alcohol before this test?
No, avoid alcohol for 24 hours before testing to prevent interference with results.
  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