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Pharmacokinetic profile of mephenytoin (or related metabolite) via mass concentration in serum/plasma

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

This test measures the amount of a specific drug or its breakdown product in your blood over time, helping doctors assess how your body processes medication.

Quick summary

["This helps tailor your medication dose to avoid side effects or ineffectiveness."]

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

Key facts at a glance

LOINC
19579-2
Short code
Me-phenidate CtO Ur Scn-mCnc
Synonyms
Me-phenidate CtO Ur Scn-mCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
screen
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What This Test Measures

The test quantifies the concentration of a drug metabolite (likely mephenytoin or a related compound) in your blood using mass concentration methods. This is often done to monitor drug levels in patients undergoing treatment with mephenytoin or similar medications.

Why It’s Done

Doctors may order this test if you’re taking mephenytoin or a related medication to ensure proper dosing. It helps prevent toxic levels (which can cause side effects) or insufficient levels (which may reduce effectiveness).

Sample Collection

A blood sample is drawn from a vein, typically in your arm. The blood is processed to separate serum or plasma for testing.

What to Expect

You may feel slight discomfort or a pinch when the needle is inserted, but it usually goes away quickly. You can resume normal activities immediately after.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

None

Frequently asked questions

Why might my doctor ask for this test?
Your doctor may recommend this test if you’re on mephenytoin or a similar medication to check how your body processes it, especially if you have kidney or liver issues or take other medications that could interact with it.
What does a low or high result mean?
Results aren’t provided with specific ranges here, but low levels might mean your body isn’t absorbing the drug well, while high levels could indicate toxicity or improper metabolism. Your doctor will interpret results in the context of your treatment.
How long will I need to fast before this test?
Fasting requirements depend on the test, but many blood tests don’t require fasting unless specified. Ask your doctor or lab technician for exact instructions.
  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