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Cycloserine concentration in serum/plasma

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

This test measures the amount of cycloserine, a medication used to treat certain bacterial infections, in your blood. It helps your healthcare provider monitor your drug levels to ensure proper dosing.

Quick summary

["This test checks if your cycloserine levels are within the target range for effective treatment."]

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

Key facts at a glance

LOINC
25209-8
Short code
cycloSERINE Islt Slgr Mcbct AB 30.0
Synonyms
cycloSERINE Islt Slgr Mcbct AB 30.0
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
method-for-slow-growing-mycobacteria-antibiotic-concentration-at-ug-ml
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 doctor may order this test if you’re taking cycloserine to treat infections like tuberculosis or leprosy. It helps ensure you’re receiving the right dose to fight the infection while avoiding harmful side effects.

What Does the Test Involve?

A blood sample is taken from a vein in your arm. The sample is sent to a lab for analysis using a high-performance liquid chromatography (HPLC) method to measure cycloserine concentration.

What to Expect Before the Test

No special preparation is needed, but inform your doctor about any medications, supplements, or recent illnesses that could affect results.

What Are Possible Results?

Results are typically reported in micrograms per milliliter (mcg/mL) or milligrams per liter (mg/L). Your doctor will interpret the results based on your medical condition and prescribed dose.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Cycloserine levels that are too low may mean your infection isn’t being controlled, while levels that are too high can increase the risk of side effects like seizures or kidney problems. Regular monitoring helps balance effectiveness and safety.

Short name

Cycloserine Level

Frequently asked questions

How often should I get this test?
Your doctor will determine the timing based on your treatment plan, but it’s often done weekly or monthly during active treatment to adjust your dose as needed.
What if my results are outside the expected range?
If your cycloserine levels are too high or too low, your doctor may adjust your medication dose or switch to a different treatment to improve outcomes and reduce risks.
Can diet or other medications affect this test?
Certain foods, vitamins, or other medications (like antibiotics) may interact with cycloserine. Always tell your doctor about all medications, supplements, or dietary changes before testing.
  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