Skip to content

Serum/plasma concentration of hydrocodone (active metabolite)

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

This test measures the amount of hydrocodone’s active metabolite in your blood, which helps assess how your body processes pain medications like Vicodin or Norco.

Quick summary

["Understanding your drug metabolism can help doctors adjust your pain treatment safely."]

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

Key facts at a glance

LOINC
73347-7
Short code
HYDROcodone+APAP ind plt IgG SerPl Ql FC
Synonyms
HYDROcodone+APAP 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

Your healthcare provider may order this test if you’re taking hydrocodone long-term, experiencing side effects, or if you have kidney issues. It helps monitor how well your body breaks down the drug and ensures safe dosing.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re anxious, let your doctor know—they may suggest ways to stay calm.

What the Results Mean

Results show how much of the active metabolite is in your blood at the time of testing. Higher-than-expected levels may indicate slower drug metabolism, while lower levels could suggest faster breakdown. Your doctor will interpret these results in the context of your symptoms and medication.

Common Causes of Abnormal Results

Results may vary based on factors like kidney function, liver health, age, or other medications you take. Kidney problems can slow drug clearance, while liver issues may affect metabolism.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for patients on long-term opioid therapy to prevent overdose risks, manage side effects, and optimize pain control. Abnormal levels may prompt dose adjustments, alternative medications, or further medical evaluation.

Short name

Hydrocodone Metabolite Level

Frequently asked questions

Why might my doctor want to check this level?
Your doctor may order this test if you’re taking hydrocodone for chronic pain, have kidney disease, or if you’re experiencing unusual side effects like dizziness, confusion, or breathing difficulties.
What does a low or high level mean?
A low level might mean your body breaks down the drug too quickly, while a high level could indicate slower metabolism or potential risks like drowsiness or slowed breathing. Your doctor will discuss these findings with you.
Can I eat or drink before this test?
You can eat and drink normally unless instructed otherwise. Avoid caffeine or alcohol before the test, as they may affect blood levels of certain substances.
  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