Test Entry - Detail

Gentamicin

General

Clinical Use:

To ascertain whether a patient is on the correct dose and the drug is at a therapeutic level.

Availability:

Samples are tested routinely during the testing laboratory's hours of operation.

Code:

GEN

Handling Instructions (to laboratory):

Send sample chilled.

Hyperlink:

Reference Interval:

Monitoring of aminoglycoside plasma concentrations should begin from the first dose if used for directed therapy, or if empiric therapy is planned to extend beyond 48 hours.
Monitoring is essential to maximise efficacy and to prevent toxicity.
For once daily dosing a computerised method approach is recommended. This requires two plasma concentrations (peak and post dose levels) 
entered into a computer program to calculate drug exposure. Discuss with a Clinical Pharmacist regarding locally available calculators. 
Trough levels should remain below the detectability of the assay.
For multiple-daily, synergistic dosing regimens (8 to 12 hourly) of gentamicin (eg for endocarditis), measure a trough (pre-dose) concentration, aiming for 0.5 to 1 mg/L.
For prolonged courses of aminoglycoside therapy (>7 days) or where high cumulative aminoglycoside exposure has occurred, regular clinical and audiologic monitoring 
is strongly recommended due to the risk of ototoxicity.
Contact an Infectious Disease Physician, Clinical Microbiologist or Clinical Pharmacist for further advice on dosing and therapeutic monitoring.

Collection Requirements

Container:

Serum, no gel (RED),

Sample Type:

See container

Minimum Collection Volume:

300uL

Collection Instructions:

If patient on once daily dosing: collect peak between 30 and 60 minutes post dose and collect trough between 6 and 14 hours post dose. For multiple-daily dosing collect trough between 6 and 14 hours post dose.
Record date, time and dosage of last dose on request form.
If sample will not reach laboratory within 24 hours of collection, it must be centrifuged and separated from gel.

Processing Requirements

Alternate Containers:

Lithium Heparin, No Gel (DKGNLITH)

Lithium Heparin-PST (GREEN)

Processing Instructions:

Minimum Assay Volume:

150uL

Stability:

24 hours chilled

Transport Instructions (to testing laboratory):

Send sample chilled.

Testing Locations

Performed at:

Section	Department	Site	Contact Phone
-	Laboratory	Albany Health Campus	9892 2240
-	Laboratory	Broome Health Campus	9194 2286
-	Laboratory	Esperance Health Campus	9079 8139
-	Laboratory	Geraldton Regional Hospital	9956 2254
-	Laboratory	Hedland Health Campus	9174 1504
-	Laboratory	Kalgoorlie Health Campus	9080 5825
-	Laboratory	Karratha Health Campus	9144 7674
-	Laboratory	Kununurra Hospital	9166 4245
Core	Biochemistry	Fiona Stanley Hospital	6152 8140
Core	Biochemistry	King Edward Memorial Hospital	6458 2753
Core	Biochemistry	QEII Medical Centre	6383 4093

Last Updated : 05-03-2025 11:23