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Test Code DIG Digoxin, Random

Additional Codes

Epic: LAB23

Specimen Required

Specimen Type: Serum

Collection Container/Type: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 3.5 mL

Collection Instructions: 

  1. Collect immediately before next dose (or at a consistent sampling time).
  2. Centrifuge within 1 hour of collection.

Additional Information:

  1. Provide date and time of last dose.

Specimen Minimum Volume

0.2 mL

Specimen Stability

Room temperature: 2 days

Refrigerated: 2 days

Frozen: 6 months

Clinical Significance

Digoxin is a potent cardiac glycoside used to treat atrial fibrillation with rapid ventricular response, and to treat congestive heart failure.  Test results are used to monitor levels of digoxin because the drug has a low therapeutic ratio (a small difference between therapeutic and tissue toxic levels), and because the symptoms of drug overdose may resemble the original condition for which the drug was prescribed.  Also, digoxin dosage may require adjustment when renal function is impaired or when drugs known to alter the pharmacokinetics of digoxin are co-administered.  Monitoring serum or plasma digoxin levels along with other clinical data can aid the physician in adjusting patient dosage to achieve optimal therapeutic effect while avoiding sub-therapeutic or toxic dosage levels. Toxic symptoms may occur at levels lower than critical limit.  Steady state is reached in 5 days.  Digoxin has an average half-life of 48 hours, is 25% protein bound, and is cleared by the kidneys.

Reference Range

Therapeutic range: 0.5 - 2.0 ng/mL

Rejection Due To

Unlabeled, mislabeled, wrong tube type, QNS, gross hemolysis

Day(s) and Time(s) Performed

Daily

Report Available

Same day

Method Name

Chemiluminescent Microparticle Immunoassay (CMIA).

Limitations

Heterophile antibodies may interfere, causing anomalous values.

Digoxin active metabolites may cross-react with methodology, which may affect test results especially in patient with renal impairment.

Endogenous digoxin-like immunoreactive factors (DLIF) found in serum of neonates, pregnant women, and in patients with renin hypertension, renal and/or hepatic failure may cause falsely elevated digoxin values.

Digoxin bound to F(ab) fragments of anti-digoxin antibodies (DIGIBIND, DIGIFAB), found in serum of patients treated for digoxin toxicity, may result in misleading digoxin values.

Quinidine may cause digoxin values to be elevated by decreasing digoxin excretion.