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Famotidine Concentration in Serum/Plasma

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

This test measures the amount of the medication famotidine in your blood. Famotidine is used to reduce stomach acid and treat conditions like heartburn, acid reflux, or ulcers.

Quick summary

["Knowing your famotidine levels helps doctors monitor your treatment and adjust your dose if needed."]

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

Key facts at a glance

LOINC
73387-3
Short code
Famotidine ind plt IgG SerPl Ql FC
Synonyms
Famotidine 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 doctor may order this test if you’re taking famotidine to check if it’s working properly. They might also do it to adjust your dose, especially if you have kidney problems or take other medications that interact with famotidine.

What to Expect Before the Test

No special preparation is needed for this test. You’ll provide a blood sample, usually drawn from a vein in your arm. The process is quick and typically painless.

How the Test Works

The test uses a sensitive method to detect famotidine in your blood. This helps measure how much of the drug is present at a given time.

Possible Results and Interpretation

Results are compared to a standard range to determine if your levels are within an expected range. Too high or too low levels may signal issues with your treatment or how your body processes the medication.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Famotidine levels help ensure you’re getting the right dose for your condition. Abnormally high levels might indicate problems with how your kidneys filter the drug, while low levels could mean your dose isn’t working as intended. This test is especially important for patients with kidney disease or those taking other medications that interact with famotidine.

Short name

Famotidine Level

Frequently asked questions

How long does it take to get my results?
Results are usually available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will contact you once they have the results.
What does a low or high famotidine level mean?
A low level might mean your dose isn’t sufficient to control your symptoms, while a high level could suggest your kidneys aren’t processing the drug properly or you’re taking too much. Your doctor will discuss these findings with you.
Can I eat or drink before this test?
You can eat and drink normally before the test, as no special preparation is required. However, always follow your doctor’s instructions if they provided any specific guidelines.
  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