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:
Tacrolimus is an immunosuppressant that is used to prevent rejection after solid organ transplantation. Studies have demonstrated that tacrolimus has clinical advantages over ciclosporin in terms of reduced incidence of acute rejection with fewer side effects. Tacrolimus has a narrow therapeutic range with frequent adverse effects 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:
Trough sample is recommended
Sample stability:
Tacrolimus is stable for at least 12 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 tacrolimus with C0 trough levels of 8 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.
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.