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HelpTest Code TACRO Tacrolimus
Useful For
Monitoring whole blood tacrolimus concentration during therapy, particularly in individuals coadministered CYP3A4 substrates, inhibitors, or inducers.
Synonyms/Keywords
FK506, Prograf
Specimen Requirements
| Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|
| Whole blood | EDTA Lavender Top Tube (LTT) | 3 mL | 1 mL | 250 uL |
Collection/Processing Instructions
1. Draw blood immediately before a schedule dose.
2. Do not centrifuge.
3. Send specimen in original tube.
Additional Information: Therapeutic range applies to trough specimens drawn immediately prior to a.m. dose.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole blood | Refrigerated (preferred) | 14 days |
| Ambient | 14 days | |
| Frozen | 14 days |
Test Information
This test was developed and its performance characteristics determined by Marshfield Labs. It has not been cleared or approved by the US Food and Drug Administration. This test is used for clinical purposes. It should not be regarded as investigational or for research.
This test is used to determine the level of tacrolimus in blood. Tacrolimus is an immunosuppressant drug that inhibits the body's immune response and is typically administered to prevent the rejection of transplanted organs, e.g. kidney and liver, or tissue, e.g. bone marrow, and may also be used to treat various autoimmune disorders such as Crohn's disease or rheumatoid arthritis. Tacrolimus has a relatively narrow therapeutic range, making drug monitoring necessary to ensure the efficacy of the treatment, and also minimize toxic side effects.
Interpretations
Most individuals display optimal response to tacrolimus with trough whole blood levels of 5.0 ng/mL to 15.0 ng/mL. Preferred therapeutic ranges may vary by transplant type, protocol, and comedications.
Therapeutic ranges are based on samples drawn at trough (ie, immediately before a scheduled dose). Blood drawn at other times will yield higher results.
Therapeutic Range:
Kidney Transplant
0-3 months post-transplant: 7.0-20.0 ng/mL
3 months and older: 5.0-15.0 ng/mL
Heart Transplant
0-3 months post-transplant: 10.0-20.0 ng/mL
3 months and older: 5.0-15.0 ng/mL
Liver Transplant
1-12 months post-transplant: 5.0-20.0 ng/mL
Toxic Value: Greater than 25.0 ng/mL
The assay is specific for tacrolimus; it does not cross-react with cyclosporine, cyclosporine metabolites, sirolimus, sirolimus metabolites, or tacrolimus metabolites. Results by liquid chromatography with detection by tandem mass spectrometry are approximately 30% less than by immunoassay.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield | 5.0-15.0 ng/mL Results are reported with a quantitative LC-MS/MS result The optimal therapeutic range may vary based on the type of transplanted organ, indication for therapy, treatment phase, time of sample collection relative to prior dose, clinical or institutional protocols and/or use with other drugs. Interpretation of results should be in conjunction with the above clinical information and any physical signs of rejection or toxicity. |
Marshfield Labs Performing Department
Marshfield Labs Special Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Friday (Prior to noon) | 1 day | Liquid Chromatography/Tandem Mass Spectrometry (LCMS/MS) using Multiple Reaction Monitoring |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 80197 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 80197 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| COM | Tacrolimus |
| Cerner | Tacrolimus Level |