FAQ | biologic kits Sanquin Reagents

The level kits are enzyme-linked immunoassays (ELISA) for fast, reproducible and specific quantitative determination of free biologic drug concentrations in human plasma and serum samples.

The ADA kits are enzyme-linked immunoassays (ELISA) for fast, reproducible and specific semi-quantitative determination of antibodies against biologic drugs in human plasma and serum samples. 

Identification of drug levels can be important for patient-adjusted treatment schedules, as low drug levels are frequently an indication for antibody formation against the provided drug. In addition, low drug levels may be a sign of ineffectiveness of adalimumab before rebound of clinical symptoms. Alternatively, it is proposed that in patients that respond well to biological drugs, the dosing of the drug can be reduced according to serum concentrations. Drug level tests can therefore help to adapt patient medication or to switch to an alternative therapy.

Together with the measurement of drug levels, the ADA kits are important for patient adjusted treatment schedules. Low drug levels are frequently an indication for antibody formation against the drug. In approximately 8% to 43% of the RA patients treated with infliximab and in 25-30% or the RA patients treated with adalimumab, antibodies are formed directed against the idiotype of the drug. 

Tumour necrosis factor (TNF) inhibitors are frequently administered to patients who suffer from diseases where inflammation is an important cause for the clinical symptoms, such as rheumatoid arthritis, intestinal bowel diseases, and psoriasis. Inhibition of the inflammation can increase the quality of life of a patient. By closely monitoring drug levels ant antibody formation in combination with disease activity, it is possible to design patient specific treatment schedules. 

Budget, cost efficient, more patients with access to biologics, cheaper tests methods available, time management, flexibility for the lab. 

The kit has been designed for professional use only, the user must be trained and familiar with ELISA test procedures. 

The level ELISA is a ‘sandwich-type’ of enzyme immunoassay. In the microtiter plates, TNF is captured by monoclonal antibodies coated to polystyrene microtiter wells. The drug present in the patient sample, the calibrator or the controls, binds to the TNF on the microtiter plate. Non-bound material is then removed by washing. Subsequently, a horseradish peroxidase-labelled monoclonal anti-drug antibody is added. This antibody binds to the drug/TNF/anti-TNF complex present in the microtiter well. After removal of non-bound HRP conjugate by washing, substrate solution is added to the wells. A coloured product is formed in proportion to the amount of the drug present in the sample, calibrator and controls. After the reaction has been terminated by the addition of a stop solution, absorbance is measured in a microtiter plate reader. From the absorbance of samples and those of the calibrator curve, the concentration of the drug can be determined by interpolation with the calibrator curve.

The ADA ELISA is a ‘sandwich-type’ of enzyme immunoassay. In the microtiter plates, the drug is captured to polystyrene microtiter wells. Free anti-drug antibodies, present in the patient sample and in the levels 1 -2 and positive and negative controls bind to the drug on the microtiter plate. Non-bound material is then removed by washing. Subsequently, horseradish peroxidase-labelled drug is added. HRP-labelled drug binds to the drug/anti-drug complex present on the surface of the microtiter well. After removal of non-bound HRP conjugate by washing, substrate solution is added to the wells. A  coloured product is formed in proportion to the amount of the anti-drug present in the sample and controls. After the reaction has been terminated by the addition of a stop solution, absorbance is measured in a microtiter plate reader. From the absorbance of samples and those of the levels, the samples can be qualified negative (-), (weak) positive (+), strong positive (++) for anti-drug antibodies. 

All kits are CE IVD certified. 

The  infliximab level test is validated for Remicade® and the biosimilars Remisma® and Inflectra®. 

Monoclonal antibodies.

ADA test: in duplo 22 samples.
Level test: in duplo 44 samples.