Etanercept (Enbrel®) ELISA Kit

Product Type:
Biosimilar ELISA
Biosimilar ELISA Type:
Free drug
Etanercept (Enbrel®)
Research Area:
Anti-TNF Alpha
Frequently bought together:



Etanercept (Enbrel®) ELISA Kit

Enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of free Etanercept (Enbrel®) in serum and plasma. The Assay Genie Etanercept (Enbrel®) ELISA Kit has been especially developed for the quantitative analysis of free etanercept in serum and plasma samples and is for research use only.

Etanercept (Enbrel®) ELISA Kit test principle

Solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle. Standards and samples (serum or plasma) are incubated in the microtitre plate coated with the reactant specific for free etanercept (Enbrel®). Following incubation wells are washed and then horse radish peroxidase (HRP) is added and binds to Etanercept. After incubation, the wells are washed, and the bound enzymatic activity is detected by addition of chromogen-substrate. The colour developed is proportional to the amount of free etanercept (Enbrel®) in the sample or standard. Results of samples can be determined directly using the standard curve.

Etanercept (Enbrel®) ELISA Kit Product Information

Information Description


Free drug

Required Volume (μl)


Total Time (min)


Sample Type

Serum, Plasma

Number of Assays


Detection Limit (ng/mL)

100 (ng/mL)

Spike Recovery (%)


Shelf Life (year)


Alternative Names

Tumour Necrosis Factor Receptor (TNFR)


Etanercept (Enbrel®) - Key Information

Etanercept (Enbrel®) mode of action

Etanercept (Enbrel®) is a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human 75 kilodalton (p75) tumour necrosis factor receptor (TNFR) linked to the Fc portion of human IgG1. The Fc component of etanercept contains the CH2 domain, the CH3 domain and hinge region, but not the CH1 domain of IgG1. Etanercept consists of 934 amino acids and has an apparent molecular weight of approximately 150 kilodaltons.

Etanercept binds specifically to tumour necrosis factor (TNF) and blocks its interaction with cell surface TNF receptors. Elevated levels of TNF are found in involved tissues and fluids of patients with rheumatoid arthritis (RA), psoriatic arthritis, ankylosing spondylitis (AS), and plaque psoriasis. Two distinct receptors for TNF (TNFRs), a 55 kilodalton protein (p55) and a 75 kilodalton protein (p75), exist naturally as monomeric molecules on cell surfaces and in soluble forms. Biological activity of TNF is dependent upon binding to either cell surface TNFR. Etanercept is a dimeric soluble form of the p75 TNF receptor that can bind to two TNF molecules. Etanercept inhibits binding of both TNF alpha and TNF beta (lymphotoxin alpha [LT alpha]) to cell surface TNFRs, rendering TNF biologically inactive.

Etanercept (Enbrel®) uses

Etanercept is a tumor necrosis factor (TNF) inhibitor used to treat various autoimmune conditions including certain types of arthritis; rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis. Etanercept is also used to treat particular skin conditions such as plaque psoriasis.

Etanercept (Enbrel®) pharmacokinetics

After administration of 25 mg of ENBREL® by a single subcutaneous (SC) injection to 25 patients with RA, a mean ± standard deviation half-life of 102 ± 30 hours was observed with a clearance of 160 ± 80 mL/hr. A maximum serum concentration (Cmax) of 1.1 ± 0.6 mcg/mL and time to Cmax of 69 ± 34 hours was observed in these patients following a single 25 mg dose. After 6 months of twice weekly 25 mg doses in these same RA patients, the mean Cmax was 2.4 ± 1.0 mcg/mL (N =23). Patients exhibited a two- to sevenfold increase in peak serum concentrations and approximately four-fold increase in AUC0-72 hr (range 1 to 17-fold) with repeated dosing. The pharmacokinetic parameters in patients with plaque psoriasis were similar to those seen in patients with RA.

In another study, serum concentration profiles at steady state were comparable among patients with RA treated with 50 mg ENBREL® once weekly and those treated with 25 mg ENBREL® twice weekly. The mean (± standard deviation) Cmax, Cmin, and partial AUC were 2.4 ± 1.5 mcg/mL, 1.2 ± 0.7 mcg/mL, and 297 ± 166 mcg·h/ mL, respectively, for patients treated with 50 mg ENBREL® once weekly (N = 21); and 2.6 ± 1.2 mcg/mL, 1.4 ± 0.7 mcg/mL, and 316 ± 135 mcg·h/mL for patients treated with 25 mg ENBREL® twice weekly (N = 16). No formal pharmacokinetic studies have been conducted to examine the effects of renal or hepatic impairment on ENBREL® disposition. Patients with juvenile idiopathic arthritis (JIA) (ages 4 to 17 years) were administered 0.4 mg/kg of ENBREL® twice weekly for up to 18 weeks. The mean serum concentration after repeated SC dosing was 2.1 mcg/mL, with a range of 0.7 to 4.3 mcg/mL.

Limited data suggests that the clearance of ENBREL® is reduced slightly in children ages 4 to 8 years. Population pharmacokinetic analyses predict that administration of 0.8 mg/kg of ENBREL® once weekly will result in Cmax 11% higher, and Cmin 20% lower at steady state as compared to administration of 0.4 mg/ kg of ENBREL® twice weekly. The predicted pharmacokinetic differences between the regimens in JIA patients are of the same magnitude as the differences observed between twice weekly and weekly regimens in adult RA patients. Patients treated with ENBREL® are at increased risk for developing serious infections that may lead to hospitalization or death. Patients should be closely monitored for the development of signs and symptoms of infection during and after treatment with ENBREL®, including the possible development of tuberculosis in patients who tested negative for latent tuberculosis infection prior to initiating therapy.

Etanercept (Enbrel®) treatment

It has been reported that patients receiving etanercept may develop antibodies that interfere with monoclonal antibody laboratory assays. Serum concentration of ENBREL® might be related to predict some clinical outcome during maintenance therapy. It was also possible that the surveillance of circulating ENBREL® concentration during maintenance therapy represents a direct and/or indirect factor for immunogenicity and some other side effects. In this context, identification of biomarkers for (non-)response and risk factors for adverse drug reactions that might be related to serum concentrations and maintaining the effective minimum concentration of ENBREL® in order to potentially avoid some side effects with a reliable method might be beneficial.

Etanercept (Enbrel®) ELISA Kit Contents

Size Kit Contents


Microtiter Plate

Break apart strips. Microtiter plate with 12 rows each of 8 wells coated with reactant.

7 x 0.3 mL

Etanercept Standards A-E, High Level Control, Low Level Control

3; 1; 0.3; 0.1 and 0 microgram/mL
Ready to use. Used for construction of the standard curve. Contains etanercept (Enbrel®), human serum, stabilizer and <0.1% NaN3.

1 x 50 mL

Assay Buffer
Blue coloured. Ready to use. Contains proteins and <0.1% NaN3.

1 x 12 mL

Horse radish peroxidase-Conjugated Probe.
Red coloured. Ready to use. Contains horse radish peroxidase and stabilizers.

1 x 12 mL

TMB Substrate Solution
Ready to use. Contains TMB

1 x 12 mL

TMB Stop Solution
Ready to use. 1N HCl

1 x 50 mL

Wash Buffer concentrate (20x)
Contains Buffer with Tween 20.

2 x 1

Adhesive Film
For covering of Microtiter Plate during incubation.

Etanercept (Enbrel®) ELISA Protocol

Steps Protocol


Pipette 100µl of Assay Buffer non-exceptionally into each of the wells to be used.


Pipette 20 µL of each ready-to use Standards, High Level Control, Low Level Control and Diluted Samples into the respective wells of microtiter plate.
A1: Standard A
B1: Standard B
C1: Standard C
D1: Standard D
E1: Standard E
F1: High Level Control
G1: Low Level Control
H1 and on: Sample (Serum / Plasma)


Cover the plate with adhesive foil. Incubate 30 min at room temperature (18- 25°C).


Remove adhesive foil. Discard incubation solution. Wash plate 3 times each with 300µL of diluted. Wash Buffer. Remove excess solution by tapping the inverted plate on a paper towel.


Pipette 100 µL of ready-to use Peroxidase into each well.


Cover the plate with adhesive foil. Incubate 30 min at room temperature (18- 25°C).


Remove adhesive foil. Discard incubation solution. Wash plate 3 times each with 300 µL of diluted Wash Buffer. Remove excess solution by tapping the inverted plate on a paper towel.


Pipette 100 µL of TMB Substrate Solution into each well.


Incubate 10 min (without adhesive foil) at room temperature (18-25°C) in the dark


Stop the substrate reaction by adding 100 µL of Stop Solution into each well. Briefly mix contents by gently shaking the plate. Colour changes from blue to yellow.


Measure optical density with a photometer at 450/650 nm within 30 min after pipetting of the Stop Solution.


Enbrel® is a registered trademark of Amgen, Inc.