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Ceftriaxone in Serum/Plasma (Quantitative)

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

This test measures the amount of ceftriaxone, a type of antibiotic, in your blood. It helps doctors check if your medication levels are within the safe range.

Quick summary

["This test helps monitor antibiotic effectiveness and adjust treatment as needed."]

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

Key facts at a glance

LOINC
73465-7
Short code
cefTRIAXone ind plt IgM SerPl Ql FC
Synonyms
cefTRIAXone 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 Is This Test Done?

Your healthcare provider may order this test if you’re taking ceftriaxone to treat infections like bacterial meningitis, pneumonia, or other serious illnesses. It helps ensure the antibiotic is working properly and isn’t causing harmful side effects.

What to Expect Before the Test

No special preparation is needed. A blood sample will be taken from a vein, usually in your arm. You may feel a brief pinch, but it’s over quickly. If you’re on other medications, let your provider know.

What the Results Mean

Results help your doctor determine if your antibiotic dose is correct. Low levels may mean the infection isn’t fully treated, while very high levels could signal side effects. Your doctor will discuss these findings with you.

Common Reasons for Testing

This test is often done during or after antibiotic treatment to check for effectiveness, monitor toxicity, or adjust dosing based on your response to the medication.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormally low or high ceftriaxone levels can affect how well the infection is controlled. Low levels might require a higher dose, while high levels could indicate kidney issues or other complications. Your doctor will use these results to guide your care.

Short name

Ceftriaxone Level

Frequently asked questions

Why might my doctor want to check my ceftriaxone levels?
Your doctor may order this test if you’re taking ceftriaxone to treat a serious infection, if you’re experiencing side effects, or if you’re having trouble with the medication working as expected.
How long will it take to get my results?
Results are typically available within 1 to 3 business days, depending on your lab. Your doctor will contact you once they’re ready.
Can I eat or drink before this test?
Yes, you can eat and drink normally before this test. No special preparation is needed.
  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