Home
HelpTest Code FRDIG Digoxin, Free, Serum
Reporting Name
Digoxin, Free, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Evaluating recrudescent (breakthrough) digoxin toxicity in renal-failure patients
Assessing the need for more antidigoxin Fab to be administered
Deciding when to reintroduce digoxin therapy
Monitoring patients with possible digoxin-like immunoreactive factors (DLIFs)
Method Name
Ultrafiltration followed by Electrochemiluminescent Immunoassay
Specimen Required
Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Draw blood 6 to 8 hours after last dose of digoxin.
2. Serum gel tubes should be centrifuged within 2 hours of collection.
3. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Type
SerumSpecimen Minimum Volume
0.6 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 180 days |
Reject Due To
| Gross hemolysis | Reject |
Reference Values
<16 years:
Therapeutic ranges have not been established for patients who are under 16 years of age. In adults, the suggested serum free digoxin therapeutic range is 0.4-0.9 ng/mL.
Toxic concentration: ≥3.0
≥16 years:
0.4-0.9 ng/mL
Toxic concentration: ≥3.0 ng/ mL
Interpretation
The target therapeutic level is 0.4 to 0.9 ng/mL. Toxicity may be seen when free digoxin concentrations are 3.0 ng/mL or higher. Pediatric patients may tolerate higher concentrations.
Therapeutic concentrations for free digoxin are 25% lower than therapeutic values for total digoxin due to the separation of protein-bound digoxin in the assay.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 dayTest Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80163
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| FRDIG | Digoxin, Free, S | 3562-6 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| FRDIG | Digoxin, Free, S | 3562-6 |
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Cardiovascular Test Request Form (T724)
-Therapeutics Test Request (T831)