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Tetracycline Concentration in Serum

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

This test measures the amount of tetracycline, a broad-spectrum antibiotic, in your blood serum. It helps monitor drug levels to ensure proper dosing and avoid toxicity.

Quick summary

["This test checks how much tetracycline is in your blood to guide treatment safety and effectiveness."]

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

Key facts at a glance

LOINC
498-6
Short code
Tetracycline Titr SBT
Synonyms
Tetracycline Titr SBT
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
sbt
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 taking tetracycline (or a related antibiotic) to ensure your dose is appropriate. It’s particularly useful for long-term use or in cases where high doses are needed, such as for severe infections.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. The process is quick and typically painless. If you’re on anticoagulants, let your provider know to avoid unnecessary bleeding.

What the Results Mean

Results show the concentration of tetracycline in your blood. Low levels may indicate insufficient absorption, while very high levels could signal toxicity. Your provider will interpret results based on your treatment plan and medical history.

Common Reasons for Testing

This test is often used in patients with kidney issues, as tetracycline is excreted through urine. It may also be checked in people with allergies to other antibiotics or those needing high-dose therapy.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Tetracycline Level

Frequently asked questions

What does a high or low tetracycline level indicate?
High levels may cause side effects like nausea, vomiting, or kidney damage. Low levels could mean the antibiotic isn’t working effectively against infections. Your provider will adjust your treatment based on these results.
How long does it take to get results?
Results are usually available within 1–3 business days, depending on your lab. You’ll be notified once they’re ready, often through your lab’s portal or a follow-up call.
Can I eat or drink before the blood draw?
Yes, you can eat and drink normally. Avoiding food or fluids for a set period isn’t required for this 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