Digoxin level

Keywords: Dig

Specimen:

5 mL blood in plain tube.

The blood specimen must be taken at least 6 h after the last oral dose of digoxin (ideally 12 h).

Method:

Immunoassay.

Therapeutic Interval:

Atrial fibrillation: 0.5-1.8 µg/L

Heart failure: 0.5-1.0 µg/L

Application:

Assessment of suspected digoxin toxicity or inadequate response. Digoxin half-life is 20-50 hours; prolonged with renal impairment.

Interpretation:

Toxic levels: >2.0 µg/L.

Concentrations >1.0 µg/L are associated with increased mortality, but may be necessary in tachyarrhythmia which is best done in consultation with a cardiologist.

Reference:

Campbell TJ et al. Med J Aust. 2003; 179: 98-102.

Rathore SS et al. JAMA. 2003; 289: 871-8.