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Tobramycin Concentration in Plasma (Serum/Plasma)

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

This test measures the amount of the antibiotic tobramycin in your blood, typically done to monitor its levels when you're taking this medication.

Quick summary

["Tobramycin levels help ensure safe and effective dosing for infections treated with this antibiotic."]

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

Key facts at a glance

LOINC
73114-1
Short code
Tobramycin ind plt IgM SerPl Ql FC
Synonyms
Tobramycin 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 Is Done

Your healthcare provider may order this test if you’re receiving tobramycin (an aminoglycoside antibiotic) to check how much of the drug is in your blood. This helps prevent harmful side effects, such as kidney damage or hearing loss, by ensuring the right balance of medication.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into a vein (usually in your arm) to draw blood. The process is quick and typically causes only minor discomfort.

What the Results Mean

Results are used to guide your treatment. Low levels may indicate the drug isn’t working well, while dangerously high levels could require dose adjustments or temporary stopping of the medication.

Possible Side Effects of Tobramycin

Tobramycin can cause side effects like dizziness, nausea, or hearing changes. Rarely, it may affect kidney function or cause allergic reactions. Always report any unusual symptoms to your doctor.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Monitoring tobramycin levels is critical for aminoglycoside antibiotics, which can accumulate in the body and harm organs like the kidneys or ears. Proper dosing prevents toxicity while ensuring the infection is fully treated.

Short name

Tobramycin Level

Frequently asked questions

What does a ‘target’ or ‘therapeutic’ range mean for this test?
A ‘target’ range is the ideal level of tobramycin in your blood, determined by your doctor based on your condition and how you respond to treatment. It balances effectiveness and safety.
Why might my tobramycin levels be checked more often?
If you have kidney problems, are elderly, or take other medications that interact with tobramycin, your doctor may check levels more frequently to avoid dangerous buildup.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor instructs otherwise. No fasting is required for this blood test.
  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