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Test ID GENRA Gentamicin, Random, Serum

Useful For

Monitoring adequacy of serum concentration during gentamicin therapy in specimens for which no collection timing information is provided

Method Name

Turbidimetric Immunoassay

Reporting Name

Gentamicin, Random, S

Specimen Type


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  14 days
  Ambient  72 hours

Reference Values

Gentamicin, Peak

Therapeutic: 3.0-12.0 mcg/mL

Toxic: >12.0 mcg/mL

Gentamicin, Trough

Therapeutic: <2.0 mcg/mL

Toxic: >2.0 mcg/mL

Day(s) Performed

Monday through Sunday

Report Available

Same day/1 day

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved or is exempt by the U.S. 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.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
GENRA Gentamicin, Random, S 35668-3


Result ID Test Result Name Result LOINC Value
GENRA Gentamicin, Random, S 35668-3

NY State Approved



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