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QuicKey Human RBP4(Retinol Binding Protein 4) ELISA Kit

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Price:   $390
Cat Number:  E-TSEL-H0006
Lead Time:   7~10 days

Reactivity:  Human

Detection Range:  3.13~100 ng/mL

Sensitivity:  1.98 ng/mL

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Product Details

QuicKey Series

Get more sensitive and precise results with saving at least 1h comparing to traditional ELISA Kits. The new developed technology in house will help to accelerate your science research in a more efficient way.


Assay type Sandwich-ELISA
Format 96T/48T
Assay time 2.5 h
Reactivity Human
Detection method Colormetric
Colormetric 3.13-100 ng/mL
Sensitivity 1.98 ng/mL
Sample volume 50μL/well
Sample type serum, plasma, urine
Specificity This kit recognizes Human RBP4 in samples. No significant cross-reactivity or interference between Human RBP4 and analogues was observed.
Reproducibility Both intra-CV and inter-CV are < 10%.
Application This ELISA kit applies to the in vitro quantitative determination of Human RBP4 concentrations in serum, plasma, urine. Please consult technical support for the applicability if other biological fluids need to be tested.

Test principle

This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to Human RBP4. Samples (or Standards) and biotinylated detection antibody specific for Human RBP4 are added to the micro ELISA plate wells. Human RBP4 would combine with the specific antibody. Then Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Human RBP4, biotinylated detection antibody and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 ± 2 nm. The OD value is proportional to the concentration of Human RBP4. You can calculate the concentration of Human RBP4 in the samples by comparing the OD of the samples to the standard curve.

Kit components & Storage

An unopened kit can be stored at 2-8℃ for six months. After test, the unused wells and reagents should be stored according to the table below. (The specific components might be slightly different in delivered kits, please refer to the manual for more information.)

Item Specifications Storage conditions after test
Micro ELISA Plate (Dismountable) 96T: 8 wells ×12 strips
48T: 8 wells ×6 strips
2-8℃, 1 month
Reference Standard 96T: 2 vials
48T: 1 vial
Discard unused reconstituted standard and dilutions
Reference Standard & Sample Diluent 1 vial, 20 mL 2-8℃
Biotinylated Detection Ab Working Solution 1 vial, 6 mL
HRP Conjugate Diluent 1 vial, 14 mL
Concentrated Wash Buffer (25×) 1 vial, 30 mL
Concentrated HRP Conjugate (100×) 96T: 1 vial, 120 μL
48T: 1 vial, 60 μL
2-8℃ (Protect from light)
Substrate Reagent 1 vial, 10 mL
Stop Solution 1 vial, 10 mL 2-8℃
Plate Sealer 5 pieces
Product Description 1 copy
Certificate of Analysis 1 copy

Note: All reagent bottle caps must be tightened to prevent evaporation and microbial pollution. The volume of reagents in partial shipments is a little more than the volume marked on the label, please use accurate measuring equipment instead of directly pouring into the vial(s).

Other supplies required

1. Microplate reader with 450nm wavelength filter

2. High-precision transfer pipette, EP tubes and disposable pipette tips

3. Incubator capable of maintaining 37℃

4. Deionized or distilled water

5. Absorbent paper

6. Loading slot for Wash Buffer

Technical Data

Sample values


Typical Standard Curve

As the OD values of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique, washing technique or temperature effects), the operator should establish a standard curve for each test. Typical standard curve and data is provided below for reference only.

Concentration(ng/mL) 100 50 25 12.5 6.25 3.13 0
OD 2.549 1.752 0.924 0.423 0.175 0.099 0.071
Corrected OD 2.478 1.681 0.853 0.352 0.104 0.028 -


Intra-assay Precision (Precision within an assay): 3 samples with low, mid range and high level Human RBP4 were tested 20 times on one plate, respectively.

Inter-assay Precision (Precision between assays): 3 samples with low, mid range and high level Human RBP4 were tested on 3 different plates, 20 replicates in each plate.

Intra-assay Precision Inter-assay Precision
Sample 1 2 3 1 2 3
n 20 20 20 20 20 20
Mean(ng/mL) 4.61 11.48 43.50 4.80 11.26 42.82
Standard deviation 0.24 0.53 1.81 0.25 0.51 1.94
CV (%) 5.21 4.62 4.16 5.21 4.53 4.53


The recovery of Human RBP4 spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

Sample Type Range (%) Average Recovery (%)
Serum(n=8) 89-102 96
EDTA plasma(n=8) 91-105 99
Urine(n=8) 89-97 92


Samples were spiked with high concentrations of Human RBP4 and diluted with Reference Standard & Sample Diluent to produce samples with values within the range of the assay.

Serum(n=4) EDTA plasma (n=4) Urine(n=4)
1:2 Range (%) 90-101 88-96 99-110
Average (%) 98 92 104
1:4 Range (%) 85-100 95-109 88-101
Average (%) 92 101 96
1:8 Range (%) 100-109 100-109 92-101
Average (%) 103 105 95
1:16 Range (%) 101-109 99-108 90-101
Average (%) 105 102 93

Target information


Retinol binding protein 4 (RBP4), previously called retinol binding protein (RBP) is a transporter protein. This protein belongs to the lipocalin family and is the specific carrier for retinol (vitamin A alcohol) in the blood [1]. It delivers retinol from the liver stores to the peripheral tissues. In plasma, the RBP-retinol complex interacts with transthyretin which prevents its loss by filtration through the kidney glomeruli. A deficiency of vitamin A, blocks secretion of the binding protein post translationally and results in defective delivery and supply to the epidermal cells.RBP4 seems to be correlated with cardio metabolic markers in inflammatory chronic diseases, including obesity, type 2 diabetes, metabolic syndrome, and cardiovascular diseases (CVDs) [2].
1. Rask L, Anundi H, Fohlman J, et al. The complete amino acid sequence of human serum retinol-binding protein. [J]. Upsala Journal of Medical Sciences, 1987, 92(2):115.
2. Bobbert P, Weithäuser A, Andres J, et al. Increased plasma retinol binding protein 4 levels in patients with inflammatory cardiomyopathy [J]. European Journal of Heart Failure, 2014, 11(12):1163-1168.

Database Links

SwissProt P02753 Human
Entrez Gene 5950 Human





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Assay procedures

1. Add 50μL standard or sample to the wells, immediately add 50μL Biotinylated Detection Ab working solution to each well. Incubate for 90 min at 37°C
2. Aspirate and wash the plate for 3 times
3. Add 100μL HRP conjugate working solution. Incubate for 30 min at 37°C. Aspirate and wash the plate for 5 times
4. Add 90μL Substrate Reagent. Incubate for 15 min at 37°C
5. Add 50μL Stop Solution
6. Read the plate at 450nm immediately. Calculation of the results
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