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Elecsys® Sirolimus
Electrochemiluminescence immunoassay (ECLIA)
for the in vitro quantitative determination of
sirolimus in human whole blood
Indication
The Elecsys Sirolimus assay is used as an aid in the management of kidney transplant patients receiving sirolimus
therapy. Organ transplant patients are prescribed with immunosuppressant drugs (ISD) like e.g. sirolimus so that the
immune system does not reject the newly transplanted organ. ISD assays are used to determine the drug concentration
in the patient’s blood as a guide for effective and well-tolerated doses as the desired therapeutic effect is only obtained
in a narrow therapeutic range: The dose must be high enough to prevent organ rejection, and low enough to avoid drug
toxicity and opportunistic infections.1
Manual sample pretreatment
The Elecsys Sirolimus assay uses human whole blood specimens as sample material. As sirolimus is largely distributed
in red blood cells and bound to proteins, a one-step manual pretreatment is performed to release the analytes from the
proteins. The pretreatment reagent and procedure is universally used for all Elecsys ISD assays.
1
300 µL of well-mixed whole
blood (or calibrator or control)
2
2.0 mL microcentrifuge tubes
300 µL of ISD
sample pretreatment
Vortex, then centrifuge
for 4 min at 10,000 g
Transfer the clear supernatant
into a new sample tube
Test principle: Competition principle
Streptavidin
microparticle
Sirolimus in the
pretreated sample
+
9 min
9 min
+
Detection
Ru
Sirolimusspecific biotinylated
antibody
Ru-labeled
sirolimus –
derivative
Ru
1st incubation (9 minutes)
35 µL of pretreated sample is incubated with an sirolimus-specific biotinylated antibody. The analytes in the sample bind to
the antibody.
2nd incubation (9 minutes)
After addition of sirolimus labeled with ruthenium complex and streptavidin‑coated microparticles, the unbound sites of
the biotinylated sirolimus-specific antibody become occupied. The entire complex becomes bound to the solid phase via
interaction of biotin and streptavidin.
Measurement
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. Application of a voltage to the electrode then induces
chemiluminescent emission which is measured by a photomultiplier.
Elecsys technology
ECL (ElectroChemiLuminescence) is Roche’s technology for immunoassay detection. Based on this technology and combined
with well-designed, specific and sensitive immunoassays, Elecsys delivers reliable results. The development of ECL immunoassays
is based on the use of a ruthenium-complex and tripropylamine (TPA). The chemiluminescence reaction for the detection of
the reaction complex is initiated by applying a voltage to the sample solution resulting in a precisely controlled reaction. ECL
technology can accommodate many immunoassay principles while providing superior performance.
Elecsys® Sirolimus test characteristics
Testing time
Test principle
Calibration
Traceability
Sample material
Sample volume
LoB, LoD, LoQ*
Measuring range
Intermediate precision (representative data)
Sample pretreatment
Expected values
18 min
Competitive assay
2 point
Standardized against gravimetrically produced master
calibrators consisting of exactly defined pure substance
sirolimus concentrations in human whole blood matrix
EDTA whole blood
300 μL
0.4 ng/mL, 0.5 ng/mL, 1.5 ng/mL
0.5 – 30 ng/mL
cobas e 411 analyzer: 2.9 – 6.2 %
cobas e 601/e 602 modules: 3.4 – 6.9 %
Lowest conc. measured: 2.62 ng/mL
One-step manual sample pretreatment; one universal reagent is
used for all ISD assays
No firm therapeutic range exists for sirolimus in whole blood.
Each laboratory should determine its own ranges based on
clinical experience.
*LoB = Limit of Blank; LoD = Limit of Detection; LoQ = Limit of Quantitation (25 % total error)
Order information
Elecsys® Sirolimus
Elecsys® Sirolimus CalSet
PreciControl ISDs
ISD Sample Pretreatment
100 tests per rackpack
3 × 1 mL each of CalSet Sirolimus
Level 1 and 2
1 × 3 mL each of PreciControl ISD
1, 2 and 3
1 × 30 mL
06327974 190
06327982 190
05889081 190
05889073 190
COBAS, COBAS E, LIFE NEEDS ANSWERS and ELECSYS are trademarks of Roche.
Not for distribution in the US.
©2015 Roche
Roche Diagnostics International Ltd
CH-6343 Rotkreuz
Switzerland
www.cobas.com
References
1 Kahan, B.D., Keown, P., Levy, G.A. et al. (2002). Therapeutic drug monitoring of immunosuppressant drugs in clinical practice. Clin Ther, 24(3), 330-350.