Digoxin - serum

Last updated: Tuesday, 30, March, 2004
Item Process
Specimen

5 mL blood in plain tube.

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

Method

Immunoassay.

Therapeutic Interval
0.6-2.3 nmol/L (0.5-1.8 µg/L).
ApplicationAssessment of suspected digoxin toxicity or inadequate response. Digoxin half-life is 20-50 hours; prolonged with renal impairment.
Interpretation

Toxic levels: >2.6 nmol/L (>2.0 µg/L).

The therapeutic interval is approximate, toxicity can occur at lower levels, especially if there is associated hypokalaemia.

Reference

Sidwell A et al. N Z Med J 2003; 12:116(1187):U708.