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Test Code BLOD0585 Digoxin, Serum or Plasma

Useful For

  • Diagnosis of digoxin toxicity
  • Monitoring therapeutic drug levels



Performing Laboratory

Bozeman Health Laboratory Services

Specimen Requirements

Blood specimens for digoxin levels should be collected between 6 and 8 hours after the last oral dose.
Specimen Type: Plasma or serum
Container/Tube: Light-green top (lithium heparin gel), red top, or gold top
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL

Collection Instructions:

1. Date and time of last dose and date and time of draw are required.

2. Label specimen as plasma or serum.

Specimen Transport Temperature

Ambient <8 hours/Refrigerated >8 hours

Specimen Stability


Specimen Type Temperature Time
Plasma or Serum Ambient 8 hours
  Refrigerated 7 days
  Frozen 6 months


Reference Values

Therapeutic concentration: 0.9-2.0 ng/mL 

Toxic concentration (automatic call-back): >2.0 ng/mL


The therapeutic range of 0.9-2.0 ng/mL includes effective serum concentrations for a wide range of patient populations, although lower concentrations of 0.5-1.2 ng/mL (0.64-1.54 nmol/L) have been found to be more appropriate in certain populations such as chronic heart failure patients. Digoxin toxicity is commonly associated with serum levels >2.0 ng/mL but may occur with lower digoxin levels. Consequently, analysis of serum concentrations alone is not sufficient for optimization of digoxin therapy. Additional factors such as age, thyroid condition, electrolyte balance, hepatic and renal functions, and other clinical symptoms must be considered.

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding