Turnaround times
The quoted turnaround time is from sample receipt in the laboratory, to results authorisation in the Laboratory Information Management system. The times do not include transport of specimen to the laboratory or the administrative process to print and post/email reports. Service users must allow for transport and reporting time when ordering tests.
Clinical background:
Sirolimus is an immunosuppressant drug that has a different mechanism of action to ciclosporin and tacrolimus and therefore can be used in addition to ciclosporin and tacrolimus or as a substitute in patients intolerant to these drugs. An advantage of using sirolimus is the lack of nephrotoxicity, especially in renal transplant patients, allowing for a reduction in the dose of ciclosporin. Adverse effects of sirolimus are generally concentration-dependent, making therapeutic drug monitoring essential for monitoring whole blood concentrations during therapy (particularly in individuals co-administered therapeutic drugs), adjusting dose to optimise immunosuppression while minimizing toxicity, and evaluating patient compliance.
Specimen container paediatric:
Pink – EDTA
Specimen container adult:
Purple – EDTA
Minimum volume paediatric:
0.5 mL blood
Minimum volume adult:
0.5 mL blood
Special requirements:
A trough sample is recommended.
Sample stability:
Sirolimus is stable for at least 6 weeks when stored at 4°C prior to analysis.
For long-term storage, samples should be stored at -15°C with stability of at least 6 months.
Transport requirements:
Ambient temperature.
Quality assurance:
International Proficiency Testing Scheme
Interpretation:
Most individuals display optimal response to sirolimus trough levels of 4 to 12 ng/mL. Preferred therapeutic ranges may vary by transplant type, length of time post-transplant and unit protocols. Please contact the original transplant unit for organ-specific therapeutic ranges.
Therapeutic ranges are based on trough levels, i.e. blood drawn immediately before a scheduled dose. Blood drawn at other times will yield higher results.
Reference ranges:
Therapeutic ranges vary with type of transplant and length of time post transplant.
Factors affecting result:
Therapeutic ranges are based on trough levels, i.e. blood drawn immediately before a scheduled dose. Blood drawn at other times will yield higher results.