DHEA-S ELISA Kit (OKAU00048)

• Product Number: OKAU00048
• Name: DHEA-S ELISA Kit (OKAU00048)
• Reconstitution and Storage: 2°C to 8°C
• Additional Information: Background: Dehydroepiandrosterone sulfate, C19H28O5S, (5-androsten-3s, 16a-diol-17-one sulfate, DHEA-S) is the major C19 steroid secreted by the adrenal cortex, and is a precursor in testosterone and estrogen biosynthesis. It is produced by the addition of a sulfate group to dehydroepiandrosterone (DHEA), catalyzed by the sulfotransferase enzymes, SULT1A1 and SULT1E1, which also produce estrone sulfate from estrone. DHEA sulfate can also be back-converted to DHEA through the action of steroid sulfatase. DHEA-S has relatively low androgenic activity due to the 17-ketone group rather than hydroxyl group. However the bioactivity of DHEA-S may be high due to its high serum concentrations at 100-1,000-fold higher than testosterone or DHEA and its weak affinity for sex-hormone binding globulin. The physiological role of DHEA-S is not well defined, with serum levels being high in the fetus and neonates, low during childhood and increased during puberty. DHEA-S levels decline during the third decade of life. DHEA-S, unlike DHEA and other steroids, does not show a significant diurnal or day-to-day variation. DHEA-S levels are not increased due to ACTH administration and do not change significantly during the normal menstrual cycle. DHEA-S has a lower metabolic clearance rate than DHEA. Since DHEA-S is primarily produced by the adrenal glands, it is useful as a marker for adrenal function. Adrenal tumors, cancers, and hyperplasia can lead to the overproduction of DHEA-S. While elevated levels may not be noticed in adult men, they can lead to amenorrhea and visible symptoms of virilization. These changes vary in severity and may include a deeper voice, hirsutism, male pattern baldness, muscularity, acne and enlargement of the Adam's apple. Women with polycystic ovary syndrome tend to have elevated levels of DHEA-S. Excess levels of DHEA-S in children can cause precocious puberty in boys; and ambiguous external genitalia, excess body hair, and abnormal menstrual periods in girls.
• Additional Information: Detection Limit: 75.6 pg/mL
• Sensitivity: 90.9 pg/mL
• Additional Information: Cross Reactivity: The following cross reactants were tested in the assay and calculated at the 50% binding point.

  Steroid	Cross Reactivity (%)	Steroid	Cross Reactivity (%)
  DHEA-S	100	Progesterone	0.2
  DHEA	162.0	Estrone	0.1
  Epiandrosterone	44.5	17OH-Progesterone	0.1
  Androsterone	28.4	17OH-Pregnenolone	< 0.1
  Androstenedione	15.2	Aldosterone	< 0.1
  DHT	0.5	Corticosterone	< 0.1
  Adrenosterone	0.4	Cholesterol	< 0.1
  Testosterone	0.4	Estradiol	< 0.1
  Desoxycorticosterone	0.2	Pregnenolone	< 0.1

  In serum the relative level of DHEA are typically between 1 and 0.1% of the DHEA-S concentration. The cross reactivity to DHEA with the assay will contribute to an increase in measured DHEA-S concentrations of less than 2%.
• Sample Type: Serum, Plasma, Urine, Saliva Dried Fecal Extracts, and Tissue Culture Media
• ELISA Kit Component:

  Component	Quantity
  Coated Clear 96 Well Plate	1 or 5 Each
  Dehydroepiandrosterone sulfate (DHEA-S) Standard	70 uL or 350 uL
  DetectX® Dehydroepiandrosterone sulfate (DHEA-S) Antibody	3 mL or 13 mL
  DetectX® Dehydroepiandrosterone sulfate (DHEA-S) Conjugate	3 mL or 13 mL
  Assay Buffer Concentrate	28 mL or 55 mL
  Wash Buffer Concentrate	30 mL or 125 mL
  TMB Substrate	11 mL or 55 mL
  Stop Solution	5 mL or 25 mL
  Plate Sealer	1 or 5 Each

• ELISA Kit Reproducibility: Intra Assay Precision Three human samples were diluted with Assay Buffer and run in replicates of 20 in an assay. The mean and precision of the calculated DHEA-S concentrations were:

  Sample	DHEA-S Conc. (pg/mL)	%CV
  1	8,148	4.6
  2	3,692	6.1
  3	920.9	10.3

  Inter Assay Precision Three human samples were diluted with Assay Buffer and run in duplicates in eighteen assays run over multiple days by four operators. The mean and precision of the calculated DHEA-S concentrations were:

  Sample	DHEA-S Conc. (pg/mL)	%CV
  1	8,567	5.2
  2	3,794	8.4
  3	932.2	11.5

• ELISA Kit Principle: The DetectX® Dehydroepiandrosterone sulfate Immunoassay kit uses a specifically generated antibody to measure Dehydroepiandrosterone sulfate (DHEA-S) in serum, plasma, urine, and saliva samples, and in fecal extracts. The kit will also quantitatively measure DHEA-S present in tissue culture media samples. Please read the complete kit insert before performing this assay. A DHEA-S standard is provided to generate a standard curve for the assay and all samples should be read off the standard curve. Standards or diluted samples are pipetted into a clear microtiter plate coated with an antibody to capture sheep antibodies. A DHEA-S-peroxidase conjugate is added to the standards and samples in the wells. The binding reaction is initiated by the addition of a polyclonal antibody to DHEA-S to each well. After a 2 hour incubation the plate is washed and substrate is added. The substrate reacts with the bound DHEA-S-peroxidase conjugate. After a short incubation, the reaction is stopped and the intensity of the generated color is detected in a microtiter plate reader capable of measuring 450 nm wavelength. The concentration of the Dehydroepiandrosterone sulfate in the sample is calculated, after making suitable correction for the dilution of the sample, using software available with most plate readers.
• ELISA Kit Linearity: Linearity was determined using human serum and urine samples, by taking samples with a high known DHEA-S concentration and a lower DHEA-S concentration and mixing them in the ratios given below. The measured DHEA-S concentrations were compared to the expected values based on the ratios used.

  High Sample	Low Sample	Expected Conc. (ng/mL)		Observed Conc. (ng/mL)		% Recovery
  		Serum	Urine	Serum	Urine	Serum	Urine
  80%	20%	30.20	23.96	30.02	24.04	99.4	100.3
  60%	40%	23.62	19.29	28.80	19.34	121.9	100.3
  40%	60%	17.05	14.62	19.82	15.70	116.2	107.4
  20%	80%	10.47	9.95	11.70	10.46	111.8	105.2
  					Mean Recovery	112.3%	103.3%

• Gene Symbol: DHEA-S
• Application: Enzyme-linked immunosorbent assay
• Image 1: ELISA Standard Curve
  
  ELISA Standard Curve