The University of Iowa (UIHC)
Department of Pathology
LABORATORY SERVICES HANDBOOK


Gentamicin
Order Code: GENT
Order Form: A-1a Therapeutic Drug Analysis or IPR Req
  Chemistry
6240 RCP
356-3527
Specimen
Plasma
Collection Medium:
Plasma separator tube
Alternate
Collection Media:
Call laboratory for additional acceptable specimen collection 
containers.
Minimum:
2 mL plasma from light green top tube or 0.6 mL light green microtube
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Analytic Time:
1 hour (upon receipt in laboratory)
Reference Range:
Peak 5-8 mcg/ml; trough 1-2 mcg/ml.
Peak levels: 45-75 min. After I.M. Dose, 15-30 min. After I.V. Dose.
Trough levels: Not more than 30 min. Before next dose.

Critical value: >15 mcg/ml
Comments:
Clinical staff must draw accurately timed peak and trough specimens.
Test
Limitations:
Sample Integrity Confirmation
Icterus: No significant interference from bilirubin up to an I index of 
60.

Hemolysis: No significant interference from hemoglobin up to an H index 
of 1000.

Lipemia: No significant interference from lipemia up to an L index of 
1000.

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.10 No representation is made by Boehringer Mannheim regarding 
the completeness of this list or the accuracy of the information 
contained therein.
Methodology:
EIA (Enzymatic ImmunoAssay)
CPT Code:
80170
 
See Additional Information:
Chemistry Critical Lab Values

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Updated: 02/23/2007

Note: The information contained in this handbook is for use by personnel of University of Iowa Health Care. No other use is implied or intended.