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HelpTest Code TOBTR Tobramycin, Trough
Specimen and Container/Tube
Specimen Type: Serum
Preferred Specimen: Red Top
Other Acceptable specimens: Li Heparin Mint Green Top, Lavendar K2 Top, Lavendar K3 Top
Specimen Handling and Transport Instructions
UCMC Onsite Instructions:
Collect specimen per standard collection procedure and send to laboratory immediately.
Recommended that serum for a trough level should be drawn 30 minutes before dose.
UCMC Offsite and UC MedLab Outreach Instructions:
- Recommended that serum for a trough level should be drawn 30 minutes before dose.
- Samples should be centrifuged within 2 hours of collection.
- Centrifuge specimens at >2500 x g for 10 minutes at room temperature.
- Aliquot sample into plastic transport tube containing a minimum of 0.2 mL of specimen.
- Samples must be sent refrigerated at 2-8oC.
Rejection Criteria
- Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits.
- Specimens that are clotted or grossly hemolyzed.
- Specimens that were transported unspun/whole blood and draw time is greater than 6 hours.
Reference Values
|
Test |
Age |
Sex |
Reference Range |
|
Tobramycin, Trough |
All |
All |
< 2 μg/mL |
Critical Values
|
Analyte |
Unit |
Low |
High |
Age |
|
Tobramycin, Trough |
μg/mL |
N/A |
> 5.0 |
> 18 years |
|
Tobramycin, Trough |
μg/mL |
N/A |
> 3.0 |
< 18 years |
CPT Codes
80200
LOINC Codes
4059-2
Volume
Preferred Volume: 0.5 mL
Minimum Volume: 0.2 mL
Specimen Stability
|
Storage Temperature |
Stability |
|
Room temperature |
N/A |
|
Refrigerated |
3 days |
|
Frozen |
1 month |
Collection Instructions
Collect specimen per standard laboratory collection procedures.
Recommended that serum for a trough level should be drawn 30 minutes before dose.
Test Components
Tobramycin
Clinical Indications
Useful for monitoring adequacy of serum concentration during tobramycin therapy.
Methodology
Homogeneous Enzyme Immunoassay (Roche Diagnostics)
Additional Information
- Results should always be assessed in conjunction with patient's medical history, clinical examination and other findings.
- Amikacin cross-reacts with this assay. Kanamycin cross-reacts significantly; however, the assay has not been optimized to quantitate this aminoglycoside. Aminoglycosides are not generally coadministered in clinical practice, although more than one aminoglycoside may be present when switching from treatment with one to another. Samples that contain tobramycin in combination with either amikacin or kanamycin cannot be reliably quantitated by this assay.
Turnaround Time
Turnaround times are relative to the time the specimen is received in the test laboratory.
STAT Turnaround Time: 1 hour
Routine Turnaround Time: 4 hours
Testing Schedule: 24/7
Synonyms/Keyword Search
N/A
Last Review Date
1/18/2023