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Beta-blocker (e.g., metoprolol, atenolol) concentration in serum/plasma

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

This test measures the amount of a medication in your blood to ensure it’s at a safe and effective level for your treatment.

Quick summary

["Your doctor uses this to check if your dose is working properly and to avoid side effects."]

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

Key facts at a glance

LOINC
47934-5
Short code
GH pre dose betaxolol+Gc SerPl-aCnc
Synonyms
GH pre dose betaxolol+Gc SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is This Test Done?

Your healthcare provider may order this test if you’re taking a beta-blocker medication to manage conditions like high blood pressure, heart rhythm issues, or angina. It helps confirm whether the dose is appropriate for your needs and whether the medication is staying within safe levels in your bloodstream.

What to Expect Before the Test

No special preparation is usually needed. You may fast for 8–12 hours before the test if instructed, but this depends on your specific medication. Bring a list of all medications you’re taking, including over-the-counter drugs.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it’s usually over quickly. The blood sample is sent to a lab for analysis.

What the Results Mean

Results help your doctor determine if your medication is working as intended. Low levels might mean your dose needs adjustment, while dangerously high levels could require immediate medical attention. Your doctor will discuss these findings with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Beta-blocker drug level

Frequently asked questions

How long does it take to get results from this test?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to review them with you.
Can I eat or drink before this test?
Follow your doctor’s instructions—some beta-blockers require fasting for 8–12 hours before testing. If unsure, ask your provider or lab technician for clarification.
What if my test results are outside the normal range?
If your levels are too low, your doctor may increase your medication dose. If they’re too high, they may adjust your treatment plan or monitor you more closely to prevent side effects like low blood pressure or slowed heart rate.
  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