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Test ID TOBRA Tobramycin, Random, Serum

Useful For

Monitoring adequacy of serum concentration during tobramycin therapy


This unit code is used whenever a specimen is submitted or collected without collection timing information. The phlebotomist should use this unit code if she or he does not know if this is a peak or trough specimen.

Method Name


Reporting Name

Tobramycin, Random, S

Specimen Type


Ordering Guidance

Serum for a peak level should be drawn 30 to 60 minutes after last dose (order TOBPA / Tobramycin, Peak, Serum).


Serum for a trough level should be drawn no more than 30 minutes before next scheduled dose (order TOBTA / Tobramycin, Trough, Serum).

Specimen Required

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Collection Instructions:

1. Serum gel tubes should be centrifuged within 2 hours of collection.

2. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  28 days
  Ambient  72 hours

Reference Values


Therapeutic: 3.0-12.0 mcg/mL

Toxic: >12.0 mcg/mL



Therapeutic: <2.0 mcg/mL

Toxic: >2.0 mcg/mL

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 to 2 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TOBRA Tobramycin, Random, S 35670-9


Result ID Test Result Name Result LOINC Value
TOBRA Tobramycin, Random, S 35670-9

NY State Approved


CPT Code Information



If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.