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Test Code GENTT Gentamicin Level, Trough, LAB26

Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements


Preferred:  Mint green-top (lithium heparin) tube

Acceptable:  Green-top tube, gold-top serum gel tube or plain, red-top tube

Specimen Volume: 0.1 mL serum or plasma

Stability:           Samples should be physically separated from cells as soon as possible with a maximum limit of 2 hours from the time of collection.    Separated specimens stored at 2 – 8°C and analyzed within 72 hour 

Collection Instructions: Trough level should be drawn immediately prior to next dose.  Specimens should not be drawn or stored in glass.

Reference Values

Therapeutic range: 0-2 mcg/mL

Critical value: >2 mcg/mL

Day(s) Test Set Up

Monday through Sunday

Useful For

Gentamicin is an aminoglycoside antibiotic which exhibits high potency and a broad spectrum bacterial action against both gram-negative and gram-positive organisms.  It exhibits a narrow therapeutic index which makes its use hazardous, especially in patients with impaired renal function.


Turbidimetric Inhibition Immunoassay

Test Classification and CPT Coding


Analytic Time

STAT within 1 hour of receipt

Routine within 2 hours of receipt