Aldosterone ELISA Kit

Sample

Extracted Serum, EDTA or Heparin Plasma, Saliva, Urine, Fecal Extracts and Tissue Culture Media

Species Reactivity

Universal

Detection Method

cELISA

Intended Use

The Aldosterone ELISA Kits measure Aldosterone present in extracted serum and plasma, or in urine, saliva, extracted dried fecal samples, and tissue culture media samples.

Contents of Kit

1. Coated Clear 96 Well Plate
A clear plastic microplate(s) with 12×8 strips coated with donkey anti-sheep IgG.
2. Aldosterone Standard
Aldosterone at 40,000 pg/mL in a special stabilizing solution.
3. Aldosterone Antibody
A sheep polyclonal antibody speciffc for Aldosterone.
4. Aldosterone Conjugate
An aldosterone-peroxidase conjugate in a special stabilizing solution.
5. Assay Buffer Concentrate
A 5× concentrate that must be diluted with deionized or distilled water.
6. Wash Buffer Concentrate
A 20× concentrate that should be diluted with deionized or distilled water.
7. TMB Substrate
8. Stop Solution
A 1M solution of hydrochloric acid.
9. Plate Sealer

Storage

All components of this kit should be stored at 4°C until the expiration date of the kit.

Precision

Intra Assay Precision
Three urine samples were diluted with Assay Buffer and run in replicates of 20 in an assay. The mean and precision of the calculated Aldosterone concentrations were:

Inter Assay Precision
Three urine samples were diluted with Assay Buffer and run in duplicates in seventeen assays run over multiple days by four operators. The mean and precision of the calculated Aldosterone concentrations were:

Detection Range

The Limit of Detection for the assay was determined in a similar manner by comparing the OD's for twenty runs for each of the zero standard and a low concentration human sample.
Limit of Detection was determined as 14.76 pg/mL

Sensitivity

Sensitivity was calculated by comparing the OD's for twenty wells run for each of the B0 and standard #6. The detection limit was determined at two (2) standard deviations from the B0 along the standard curve.
Sensitivity was determined as 4.97 pg/mL.

General Description

Aldosterone, C₂₁H₂₈O₅, is a mineralocorticoid ffrst isolated by the husband and wife team of Simpson and Tait at University College, London in 1953. Initially called electrocortin, 21 mg was isolated from 500 kg of beef adrenal glands. Aldosterone controls the sodium-potassium balance through the unidirectional salt reabsorption in a variety of tissues and glands. Synthesized from cholesterol in the zona glomerulosa of the adrenal cortex, secretion is regulated through the renin-angiotensin system. Angiotensin II and potassium stimulate primary secretion by increasing the rate of production of the steroid. Peripheral aldosterone levels are dependant on age and body position and in a normal upright adult aldosterone levels are typically less than 300 pg/mL. Aldosterone is typically secreted as the 18-glucuronide and the terahydro-3-glucuronide and this excretion is generally 2-20 μg/24 hour urine collection.

Aldosterone measurement is useful in the investigation of primary aldosteronism (i.e., adrenal adenoma or carcinoma and adrenal cortical hyperplasia) and secondary aldosteronism (renovascular disease, salt depletion, potassium loading, cardiac failure with ascites, pregnancy, Bartter syndrome). The renin-angiotensin system is the primary regulator of the synthesis and secretion of aldosterone. Increased concentrations of potassium in the plasma may directly stimulate adrenal production of the hormone. Under physiologic conditions, pituitary adrenocorticotropic hormone is not a major factor in regulating aldosterone secretion.

Standard Curve

Average the duplicate OD readings for each standard and sample. Create a standard curve by reducing the data using the 4PLC fitting routine on the plate reader, after subtracting the mean OD's for the NSB. The sample concentrations obtained, calculated from the %B/B0 curve, should be multiplied by the dilution factor to obtain neat sample values.