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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Digoxin

Test Code(s): DIGO / DIG

CPT Code(s): 80162

Methodology: Chemiluminescent Immunoassay

Clinical Significance: Cardiotonic

Days Performed: Daily, 24 hours.

Turnaround Time: Stat: 1 hour.
Routine: 4 hours.


Specimen Requirements

Specimen: Blood

Collection Instructions: Collection of specimen must be at least 6 hours after an IV dose or at least 8 hours after a PO dose.

Collection Container: Preferred: Red top
Also Acceptable: Green top

Collection Volume: Preferred: 2 mL
Pediatrics: 0.4 mL

Sample Analyzed: Serum

Volume Required: Preferred: 1 mL
Pediatrics: 0.2 mL

Specimen Processing: Centrifuge.  Transfer cell-free serum or plasma to plastic vial.  Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Unacceptable Criteria: Specimens collected in red cap with yellow ring (SST) or green cap with yellow ring (PST) tubes are not acceptable.

Stability: Ambient: 2 hours on cells; 8 hours off cells
Refrigerated: 7 days
Frozen: 6 months


Interpretation

Generally effective therapeutic concentration: 0.5-0.9 ng/mL

Test Limitations:

Administration of Digibind makes Digoxin levels invalid until Digibind (digoxin immune fab) has been cleared from the patient's system, approximately six weeks.

Endogenous, digoxin-like immunoreactive factors (DLIF) have been detected in the serum and plasma of neonates, pregnant women, and patients in renal and hepatic failure.  Several studies have established that these factors can cause falsely elevated digoxin measurements when assayed by commercially available immunoassays.

Critical Calls: View

Additional Information:

Result of "BELOW" indicates that the result is below the method detection limit of 0.06 ng/mL. Patient response to the drug varies. Potassium depletion increases sensitivity to the drug. Renal dysfunction decreases elimination of digoxin, causing an accumulation of the drug in the serum. Half-life is 32-48 hours depending on patient's renal function and can be 100 hours in anephric patients.

Lanoxin

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