Tobramycin Assay (Provide Clinical Details)
The Tobramycin Assay measures blood levels of the antibiotic tobramycin to ensure safe and effective treatment. It is essential for monitoring therapy and preventing toxicity.
Turnaround time
Results available 3 days after arrival in lab. Doctor's report sent the day after results available (if required)
Biomarkers count
1
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Details about Tobramycin Assay (Provide Clinical Details)
What is the Tobramycin Assay?
The Tobramycin Assay is a blood test used to measure the concentration of tobramycin, an aminoglycoside antibiotic, in the bloodstream. Tobramycin is commonly used to treat serious bacterial infections, particularly those caused by Gram-negative organisms.
Because tobramycin has a narrow therapeutic range, blood levels must be carefully monitored. Levels that are too low may reduce treatment effectiveness, while levels that are too high increase the risk of kidney and hearing damage.
This test is part of therapeutic drug monitoring (TDM) and is typically requested with clinical details such as dosing time, dose amount, and indication.
Why do I need a Tobramycin Assay?
Tobramycin can accumulate in the body, especially in people with reduced kidney function. Monitoring blood levels helps balance effectiveness with safety.
You may need this test if you:
- Are receiving intravenous or inhaled tobramycin
- Are being treated for severe or resistant infections
- Have kidney impairment or fluctuating renal function
- Require dose optimisation during treatment
- Are receiving prolonged antibiotic therapy
- Need monitoring due to age or comorbidities
- Are at risk of antibiotic-related toxicity
Providing clinical details ensures results are interpreted correctly.
Benefits of the test
- Ensures effective antibiotic dosing
Confirms therapeutic drug levels are achieved. - Reduces toxicity risk
Helps prevent kidney and hearing damage. - Supports dose optimisation
Enables safe adjustment of treatment. - Essential in serious infections
Used in hospital and specialist care. - Accounts for kidney function changes
Adjusts dosing in renal impairment. - Objective therapeutic monitoring
Provides precise drug concentration data. - Improves treatment safety
Reduces complications from overdosing. - Clinically guided interpretation
Results are tailored using dosing information.
Step-by-step: How we offer testing
Clinic-based testing (UK-wide)
- Choose your nearest UK clinic
- Attend your appointment
- Blood sample taken at a specific time (peak or trough)
- Clinical details recorded (dose, timing, indication)
- Sample sent to the laboratory
Home or hospital-based sampling (+£60 where applicable)
- Mobile phlebotomist arranged when appropriate
- Blood drawn at the correct time relative to dosing
- Sample securely transported to the laboratory
Your results explained
Low level (sub-therapeutic)
- Tobramycin concentration below target range
- UK standards (typical trough): <1 mg/L
- May reduce treatment effectiveness
Therapeutic level
- Tobramycin within target range
- UK standards (typical):
- Peak: 5–10 mg/L
- Trough: <1–2 mg/L
- Suggests appropriate dosing
High level (toxicity risk)
- Tobramycin above recommended range
- UK standards:
- Trough: >2 mg/L
- Increased risk of nephrotoxicity and ototoxicity
Target ranges may vary depending on indication and dosing regimen.
How It Works
Simple steps to get your results
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Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
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WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.