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HelpTest Code SIRO Sirolimus, Blood
Useful For
Monitoring whole blood sirolimus concentration during therapy. May be especially useful for individuals alsoadministered CYP3A4 substrates, inhibitors, or inducers.
Synonyms/Keywords
Rapamycin, Rapamune
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Whole Blood | EDTA Lavender Top Tube (LTT) |
|
3 mL | 1 mL | 250 uL |
Acceptable Specimen Types
Whole Blood
Collection/Processing Instructions
Collection Processing Instructions:
1. Draw blood immediately before a scheduled dose.
2. Do not centrifuge.
3. Send specimen in original tube. Do not aliquot. Aliquots will be rejected.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood EDTA | Refrigerated (preferred) |
28 days |
| Frozen | ||
| Ambient | 2 days |
Test Components
Quantitation of sirolimus level in whole blood
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.
Sirolimus is an immunosuppressant commonly used to weaken the body's immune system to prevent rejection of organ transplant. It is also used to treat lymphangioleiomyomatosis-LAM (lung disease). Sirolimus has a relatively narrow therapeutic range, making drug monitoring necessary to ensure the efficacy of the treatment, and also minimize toxic side effects.
Interpretations
Trough (ie, sample drawn immediately before a scheduled dose) Sirolimus concentrations are generally measured every 5 days. Blood drawn at other times will yield higher results.
Most individuals display optimal response to sirolimus with trough whole blood levels 4.0 to 20.0 ng/mL. Preferred therapeutic ranges may vary by transplant type, protocol, and co-medications. Target concentrations vary depending on concomitant therapy, time post-transplant, the desired degree of immunosuppression, and adverse effects. When given with cyclosporine or tacrolimus, the therapeutic range for sirolimus is generally between 4 and 12 ng/mL, with minimal added benefit for concentrations >10 ng/mL. When sirolimus is given without calcineurin inhibitors, higher trough levels are needed; usually 12 to 20 ng/mL, but occasionally up to 20 to 30 ng/mL.
The assay is specific for sirolimus; it does not cross-react with tacrolimus, everolimus, cyclosporine, or any of their metabolites.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield | 5.0 - 15.0 ng/mL (Trough) 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 12 pm) | 1 day | Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 80195 |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 80195 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Sirolimus, Blood (SIIRO) |