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HelpTest Code Billings Clinic: 4358 Gentamicin, Peak, Plasma or Serum
Performing Laboratory
Billings Clinic Laboratory: Chemistry
Useful For
Monitoring adequacy of serum concentration during gentamicin therapy
Methodology
PETINIA / Turbidimetric Rate
Specimen Requirements
Submit only 1 of the following specimens:
Serum or plasma should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.
- Plasma or serum for a peak level should be drawn 30 to 45 minutes after completion of infusion of an intravenous dose.
- Date and time of last dose are required on request form for processing.
- Indicate plasma or serum on request form.
- Label specimen appropriately (plasma or serum).
Plasma
- Draw blood in a green-top (lithium heparin) tube(s).
- Spin down and send 1 mL of heparinized plasma frozen in plastic vial.
Serum
- Draw blood in a plain, red-top tube(s).
- Spin down and send 1 mL of serum frozen in plastic vial.
Storage/Stability
| Specimen Type | Temperature | Time |
| Plasma, Serum | Refrigerated | 2 days |
| Frozen (preferred) | 1 month | |
| Ambient | 8 hours |
Reference Values
Therapeutic concentration:
Cystic Fibrosis: 20 - 35 ug/mL
Extended Interval Dosing: 20 - 25 ug/mL
Traditional Dosing: 5 - 12 ug/mL
Synergy: 3 - 5 ug/mL
Call-back toxic concentration value:
>35.0 µg/mL
Day(s) Test Set Up
Daily
Test Classification and CPT Coding
80170 - Gentamicin
LOINC Code Information
| Reporting Name | LOINC Code |
| Gentamicin Peak | 3663-2 |
| Gent Pk Dose and Time | 45285-4 |