Gentamicin, Peak

Gentamicin, Peak

Epic Mnemonic
Sunquest Mnemonic

LAB28
GENTP

Category

Chemistry

Methodology

Immunoturbidimetric assay

Test Performance Schedule

Sunday - Saturday

Result Availability

Within 24 hours – STAT upon request

Container

Gold top (SST), Red top (serum), or Green top (lithium heparin) tube

Volume

Pref. Vol.: 1.0 mL serum
Min. Vol.: 0.5 mL serum

Collection Instructions

• Recommended collection times for peak levels are:

IV infusion: 30 minutes after end of 1 hour infusion
IM injection: 60 minutes after time of injection

• Routine venipuncture

• Immediately after collection, gently invert tube 5-10 times

• Clot 30 minutes

• Promptly centrifuge 10 minutes

• If no gel barrier is present immediately transfer serum or plasma to a plastic tube and refrigerate

• Properly centrifuged gel barrier tube does not require transfer of serum or plasma to separate tube

Transportation Instructions

Refrigerated

Stability

• Refrigerated: 5 days

Causes for Rejection

Mistimed collection

Remarks

Patient Preparation:
• Administer IV infusions over a 60 minute time period
• Document exact start and end times of infusions, or exact times of injections, on requisition

CPT Codes

80170

Effective/Revised

03/23/2017

Gentamicin is used in the treatment of serious infections involving aminoglycoside-sensitive organisms.

Monitoring gentamicin concentration in serum or plasma, along with careful clinical assessment, is the most effective means of ensuring adequate therapy. Gentamicin concentration correlates better with antibacterial activity than dosage. A standard dose of gentamicin does not always yield a predictable concentration because drug concentration depends on patient’s volume of distribution and on drug elimination. The mode of administration, the volume of extracellular fluid, renal retention, and physiological change influence these factors during therapy. Gentamicin has a narrow range of safe and effective concentration. Exposure to high concentrations for a prolonged period may cause renal impairment or ototoxicity. Patients with impaired renal function should be monitored closely while on gentamicin therapy because nephrotoxicity caused by gentamicin may be difficult to distinguish from symptoms of underlying renal disease.