L-Quinolinic Acid (Urine) ELISA Assay Kit
L-Quinolinic Acid Urine ELISA Assay Kit manufactured in Germany by Immundiagnostik
Size: 1×96 wells
Standard Range: 3-300 µM
Incubation Time: Overnight; 1 h; 12-18 min
Sample Type: Urine
Sample Size: 50 µL
For Research Use Only
This L-Quinolinic Acid Urine ELISA Assay Kit is designed for the quantitative determination of quinolinic acid. The assay is based on the method of competitive enzyme linked immunoassays. Samples, standards and controls are incubated in wells of a microtiter plate coated with quinolinic acid (antigen), together with a polyclonal anti-quinolinic acid antibody. The free target antigen in the sample competes with the antigen immobilized on the wall of the microtiter wells for the binding of the polyclonal antibodies.
In the second incubation step, a peroxidase-conjugated antibody is added to each microtiter well to detect the anti-quinolinic acid antibodies. After a washing step to remove the unbound components, the peroxidase substrate tetramethylbenzidine (TMB) is added. Finally, the enzymatic reaction is terminated by an acidic stop solution. The colour changes from blue to yellow and the absorbance is measured in the photometer at 450 nm. The intensity of the yellow colour is inverse proportional to the quinolinic acid concentration in the sample. This means, high antigen concentration in the sample reduces the concentration of antibodies bound to the antigen on the plate and lowers the photometric signal. A dose response curve of the absorbance unit (optical density, OD at 450 nm) vs. concentration is generated, using the values obtained from the standards. Quinolinic acid present in the patient samples is determined directly from this curve.
Based on internal studies with urine samples of apparently healthy persons, a median of 2.2 µmol/mmol creatinine was measured (n=61). The range between the 10th and 90th percentile was 1.2-3.9 µmol/mmol creatinine. We recommend each laboratory to establish its own reference range.