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Famotidine Concentration in Serum/Plasma (Quantitative Measurement)

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

This test measures the amount of the medication famotidine in your blood, either in serum or plasma. Famotidine is used to reduce stomach acid and is often prescribed for conditions like heartburn, acid reflux, or ulcers.

Quick summary

Knowing your famotidine levels helps doctors monitor your treatment and ensure it’s working safely.

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

Key facts at a glance

LOINC
73386-5
Short code
Famotidine ind plt IgM SerPl Ql FC
Synonyms
Famotidine ind plt IgM 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 Might Be Ordered

Your doctor may recommend this test if you’re taking famotidine long-term, experiencing unusual side effects, or if your symptoms don’t improve as expected. It can also help check for drug interactions or adjust your dosage.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for a few hours before the blood draw if your lab uses a fasting protocol. Bring your current medication list to confirm famotidine is still part of your regimen.

What Happens During the Test

A healthcare provider will draw blood from a vein in your arm. The sample is then sent to a lab to measure famotidine levels using a specialized immunoassay method.

What the Results Mean

Results are typically reported in micrograms per milliliter (mcg/mL). Higher-than-expected levels might indicate overmedication, while lower levels could suggest your body isn’t absorbing the drug properly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal famotidine levels can signal issues like poor drug absorption, liver impairment, or potential interactions with other medications. Your doctor will use these results to adjust your treatment plan, ensuring you get the right balance of safety and effectiveness.

Short name

Famotidine Level

Frequently asked questions

How long does it take to get my results?
Results are usually available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to discuss them.
Can I stop taking famotidine before this test?
Only stop taking famotidine if your doctor instructs you to do so. Stopping abruptly could worsen your symptoms or cause withdrawal effects. Always follow your prescriber’s guidance.
What if my levels are too high or too low?
If levels are outside expected ranges, your doctor may adjust your dose, switch to a different medication, or investigate other health factors affecting your treatment. They’ll work with you to find the best solution.
  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