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Test ID: Sirolimus
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Sirolimus
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Useful For
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Aid in the management of kidney transplant patients receiving Sirolimus therapy.
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Method name and description
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Electrochemiluminescence Immunoassay (ECLIA)
Electrochemiluminescence immunoassay (ECLIA) intended for use on the cobas e 801 immunoassay analyzer. Patient specimen is pretreated with Elecsys ISD Sample Pretreatment, centrifuged and an aliquot of the resulting supernatant is assayed for sirolimus level. Pretreated specimen with sirolimus‑specific biotinylated antibody and a ruthenium complex labeled sirolimus‑derivate forms a complex. After addition of streptavidin-coated microparticles, the complex becomes bound to the solid phase via interaction of biotin and streptavidin. The reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of the electrode. Unbound substances are then removed with ProCell/ProCell II M. Application of a voltage to the electrode then induces chemiluminescent emission which is measured by a photomultiplier. Results are determined via a calibration curve which is instrument specifically generated by 2‑point calibration and a master curve.
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Clinical information
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Sirolimus (also called Rapamycin) is a macrocyclic antibiotic produced by the bacterium Streptomyces hygroscopicus. FDA approved Sirolimus for use in the prevention of kidney transplant rejection. mTOR inhibitors such as sirolimus and everolimus provide a means of reducing the exposure of transplant patients to calcineurin inhibitors thus potentially limiting renal toxicity in non-renal transplant patients and improving long-term allograft survival in kidney transplant patients. Common side effects include hypertension, hyperlipidemia, anemia, thrombocytopenia, electrolyte disturbances (hypokalemia and hypophosphatemia), peripheral edema, abdominal pain, arthralgia, skin disorders, pyrexia, headache, nausea, diarrhea or constipation, and a higher incidence of lymphoceles. Therapeutic drug monitoring (TDM) of sirolimus trough concentrations (C0) is necessary, especially due to the wide inter- and intra-individual variability in the pharmacokinetic behavior of the drug. The predose (trough or C0) sample is a good reflection of total exposure, as measured by area under the time-concentration curve(AUC). Good correlation has been shown between sirolimus C0 concentrations and AUC. This is also the case when the drug is used in combination with cyclosporine or tacrolimus
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Specimen type / Specimen volume / Specimen container
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Specimen type: Whole blood
Minimum volume of sample: 1 mL
Hemolysate: K2‑EDTA and K3‑EDTA tube
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Collection instructions / Special Precautions / Timing of collection
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Collect blood by standard venipuncture techniques as per specimen requirements. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
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Storage and transport instructions
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Storage: 5 days at 15 – 25°C
7 days at 2 – 8°C;
6 months at ‑20 °C or lower
Transport: 2-25°C
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Specimen Rejection Criteria
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Wrong collection container, insufficient sample, clotted sample and heat‑inactivated samples.
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Biological reference intervals and clinical decision values
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Interpretative data:
Therapeutic range for Sirolimus is generally between 4 and 12 ng/ml. When Sirolimus is given without calcineurin inhibitors, higher trough levels are needed; usually 12 to 30 ng/ml.
“The testing method is an Electrochemiluminescence Immunoassay manufactured by Roche Diagnostics and performed on Cobas e-411”.
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Turnaround time / Days and times test performed / Specimen retention time
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Daily (24/7)
Turn-around time:
STAT: 1 hour
Routine: One working day
Specimen Retention: 4 days
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