Container/Tube: Serum gel tube
Specimen Volume: 2.5 mL of serum
Transport Temperature: Refrigerated
Collection Instructions: Centrifuge specimens and remove the serum or plasma from the cellular material within 1 hour of collection.
Random: Patient must be receiving gentamicin. Random level may be ordered at any time but must be drawn at time specified by doctor, which is usually 8 to 12 hours after dose.
Peak/Trough: For patients receiving gentamicin via conventional dosing methods peak and trough drug monitoring should begin after a steady state is achieved (usually after 3–4 doses). Samples for peak concentrations should be collected 60–90 minutes after intravenous infusion. Samples for trough concentrations should be collected within 30 minutes of the next dose.
For patients receiving gentamicin via a pulse-dosing method, monitoring can begin after the first dose because steadystate conditions are not obtained. Monitoring strategies will vary with dosing regimens. When using pulse dosing nomograms, a timed sample should be collected 8–12 hours after completion of drug infusion in order to determine the subsequent dosing interval. This should be repeated at 3–7 day intervals or more frequently as warranted.
Note: Concentrations of β-lactam antibiotics (penicillins and cephalosporins) at therapeutic levels may inactivate gentamicin in vivo and in vitro. Specimens from patients receiving β-lactam antibiotics (penicillins and cephalosporins) must be analyzed immediately upon receipt or stored frozen to prevent in vitro inactivation of gentamicin.
Enzyme-Multiplied Immunoassay Technique (EMIT®)
0-6.0 µg/mL
Critical value (automatic call-back): >10 µg/mL
Monday through Sunday
Available STAT
80170