Gentamicin Drug Level
Label Mnemonic: GENT
Epic code: LAB28
Downtime form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
6240 RCP
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
3 mL plasma from light green top tube or ONE Microtainer®
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
Reference range in Epic applies to trough levels when expected 
value should be <= 1.0 μg/mL. Trough levels should ideally be 
collected not more than 30 min. before next dose.

Different target range would apply to peak levels.  Approximate target 
peak: 5-8 μg/mL. 

Peak levels: 45-75 min. after I.M. dose, 15-30 min. after I.V. dose.
Critical value: >15 μg/mL
Clinical staff must draw accurately timed peak and trough specimens. Reference range changed 12/5/17.
Test Limitations:
Sample Integrity Confirmation
Icterus: No significant interference from bilirubin up to an I index of 20.

Hemolysis: No significant interference from hemoglobin up to an H index of 2000.

Lipemia: No significant interference from lipemia up to an L index of 1691.

Sisomicin shows significant interference (greater than 50%) with the assay.

The Gentamicin II System Pack assay performance has not been established with body fluids other than human serum and heparin or EDTA plasma.

As with any assay employing mouse antibodies, the possibility exists for interference by human anti-mouse antibodies (HAMA) in the sample, which could cause falsely elevated results.

The incidence of patients having antibodies to E. coli beta-galactosidase is extremely low. However, some samples containing such antibodies can result in artificially high gentamicin results that do not fit the clinical profile. If this occurs, contact Customer Technical Support at 1-800-428-2336 for assistance.

A list of substances known to affect gentamicin levels in vivo is given by Young. No representation is made by Boehringer Mannheim regarding the completeness of this list or the accuracy of the information contained therein.
EIA (Enzymatic Immunoassay)
CPT Code:
See Additional Information:
Chemistry Critical Lab Values