21-OH Ab ELISA

Enzyme immunoassay for the quantitative determination of 21-OH Ab in human serum.

INTENDED USE:The RSR 21-hydroxylase autoantibody (21-OH Ab) ELISA kit is intended for use by professional persons only, for the quantitative determination of 21-OH Ab in human serum. Autoimmune destruction of the adrenal cortex is the most common cause of Addison’s disease and autoantibodies to the adrenal specific enzyme steroid 21 hydroxylase are important markers of adrenal autoimmunity. This can be the case if the disease presents as Addison’s disease or as part of the autoimmune polyglandular syndromes (APS) type I or type II.

GENERAL INFORMATION:In RSR’s 21-OH Ab ELISA kit, 21-OH Ab in patients’ sera, reference preparation or calibrators (optional) and controls are allowed to interact with 21-OH coated onto ELISA plate wells. After a 16 - 20 hour incubation, the samples are discarded leaving 21-OH Ab bound to the 21-OH coated on the wells. 21-OH-Biotin is added in a 2nd incubation step where, through the ability of 21-OH Ab to act divalently, a bridge is formed between the 21-OH immobilised on the plate and 21-OH-Biotin. The amount of 21-OHBiotin bound is then determined in a 3rd incubation step involving addition of streptavidin peroxidase (SA-POD), which binds specifically to biotin. Excess, unbound SA-POD is then washed away and addition of the peroxidase substrate 3,3’,5,5’-tetramethlybenzidine (TMB) results in formation of a blue colour. This reaction is stopped by the addition of a stop solution, causing the well contents to turn yellow. The absorbance of the yellow reaction mixture at 450nm and 405nm is then read using an ELISA plate reader. A higher absorbance indicates the presence of 21-OH Ab in the test sample. Reading at 405nm allows quantitation of high absorbances. It is recommended that low absorbance values are measured at 450nm. If it is possible to read at only one wavelength 405nm may be used.

KIT CHARACTERISTICS:
- Method: ELISA
- 96 tests
- Incubation Time / Conditions: 16-20 h (2-8°C), 1 h (RT/shaker), 20 min (RT/shaker), 20 min (RT/dark)
- Standard Range: 0.3 – 100 U/ml
- Sensitivity analytical: 0.13 U/ml
- Final Sample Volume: 50 µl
-Sample Type: serum
- Isotope / Substrate: TMB 450 nm
- Internal Controls: 2
- Regulatory Status: CE