Tobramycin

Clinical Biochemistry

Tobramycin levels are performed at Clinical Biochemistry GRH.
Please routinely request tobramycin levels electronically in Sunrise - send requests and collected specimens directly to Clinical Biochemistry (not Microbiology) to avoid delays in sample receipt and analysis.
Most tobramycin levels are a planned non-urgent investigation. Tobramycin levels can be taken at any time of day but the collection time should be convenient for the patient and for the testing laboratory – sampling and testing between 12 midnight and 6 am should be avoided.
For most patients requiring a tobramycin course a once daily dosing regime can be used - See Tobramycin Policy for details.
For paediatric patients, please refer to the Paediatric Cystic Fibrosis action card for Tobramycin

All patients receiving tobramycin must have levels monitored, primarily to avoid renal toxicity
Renal function should also be regularly monitored
Please refer to Tobramycin Policy for further details on when samples should be collected.

Samples must NOT be taken via lines.

For adults, blood taken into a 5mL gold top gel tube (or rust top for the Acute Unit).

For children, blood taken into a 3.5mL rust top gel tube

Do not store. Send at ambient temperature to the laboratory as soon as possible.

The assays are run throughout the day and night. The in-lab turnaround time is less than 6 hours.
Results are made available on the computer as soon as they are technically approved. Additional comments may be added later by the Consultant Microbiologist when results are clinically approved.
The test can be ordered as an urgent investigation.

Please refer to the Antibiotic Guidelines Page for information regarding therapeutic ranges.

If there is any doubt regarding interpretation, or a dose change needs to be discussed, contact the Consultant Microbiologist.

If you need advice please contact the duty consultant microbiologist or ward pharmacist.

Page last updated: 06/01/2026 | Page last reviewed: 06/01/2026