Product: Aldosterone ELISA
: 96 wells
: serum, plasma, urine
: dilute urine samples 1:50
: 50 µl
: 15 – 1,000 pg/ml
: 1 h, 20 min (RT/shaker)
: TMB at 450 nm
: 10 pg/ml
1 INTENDED USE
For the direct quantitative determination of Aldosterone in human serum, plasma and urine by an enzyme immunoassay. For in vitro diagnostic use only.
2 PRINCIPLE OF THE TEST
The principle of the following enzyme immunoassay test follows the typical competitive binding scenario. Competition occurs between an unlabelled antigen (present in Calibrators, control and patient samples) and an enzyme-labelled antigen (conjugate) for a limited number of antibody binding sites on the microwell plate. The washing and decanting procedures remove unbound materials. After the washing step, the enzyme substrate is added. The enzymatic reaction is terminated by addition of the stopping solution. The absorbance is measured on a microtiter plate reader.
The intensity of the colour formed is inversely proportional to the concentration of aldosterone in the sample. A set of Calibrators is used to plot a Calibrator curve from which the amount of aldosterone in patient samples and controls can be directly read.
3 CLINICAL APPLICATIONS
Aldosterone is a potent mineral corticoid whose synthesis and release are controlled by the renin-angiotensin system of the body. Aldosterone promotes the reabsorption of sodium in the distal tubules of the kidney resulting in potassium secretion along with sodium retention, which controls the circulating blood volume. Chronic overproduction and secretion of aldosterone leads to hypertension.
Measurement of aldosterone levels in serum in conjunction with plasma renin levels can be used to differentiate between primary and secondary aldosteronism.
The measurement of aldosterone in concert with selective suppression and stimulation tests can be used to further differentiate primary aldosteronism into two basic types:
- Primary aldosteronism caused by an adenoma of one or both adrenals.
- Primary aldosteronism caused by adrenal hyperplasia.
This differentiation is vital in the treatment and management of the disease. The adrenal adenomas respond well to surgery whereas hyperplastic disease of the adrenals is generally better managed medically. In summary, the precise and accurate measurement of serum aldosterone by enzyme immunoassay can be an important adjunct to a diagnostic laboratory battery for the differential diagnosis of hypertensive disease.