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Human CD28(Cluster Of Differentiation 28) ELISA Kit
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ELK0672
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48 T $320.00
96 T $458.00
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Overview

Product name: Human CD28(Cluster Of Differentiation 28) ELISA Kit
Reactivity: Human
Alternative Names: Tp44
Assay Type: Sandwich
Sensitivity: 0.32 ng/mL
Standard: 50 ng/mL
Detection Range: 0.78-50 ng/mL
Sample type: serum, plasma, cell lysates and other biological fluids
Assay length: 3.5h
Research Area: CD & Adhesion molecule;Tumor immunity;Infection immunity;Immune molecule;
Uniprot ID: P10747
Test principle: The test principle applied in this kit is Sandwich enzyme immunoassay. The microtiter plate provided in this kit has been pre-coated with an antibody specific to Human CD28. Standards or samples are added to the appropriate microtiter plate wells then with a biotin-conjugated antibody specific to Human CD28. Next, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. After TMB substrate solution is added, only those wells that contain Human CD28, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450nm ± 10nm. The concentration of Human CD28 in the samples is then determined by comparing the OD of the samples to the standard curve.

Standard curve

Concentration (ng/mL) OD Corrected OD
50.00 1.933 1.832
25.00 1.587 1.486
12.50 1.168 1.067
6.25 0.828 0.727
3.13 0.625 0.524
1.57 0.239 0.138
0.79 0.157 0.056
0.00 0.101 0.000

Precision

Intra-assay Precision (Precision within an assay)：CV%<8%

Three samples of known concentration were tested twenty times on one plate to assess intra-assay precision.

Inter-assay Precision (Precision between assays)：CV%<10%

Three samples of known concentration were tested in forty separate assays to assess inter-assay precision.

Recovery

Matrices listed below were spiked with certain level of recombinant CD28 and the recovery rates were calculated by comparing the measured value to the expected amount of CD28 in samples.
Matrix Recovery range Average
serum(n=5) 96-109% 102%
EDTA plasma(n=5) 82-95% 88%
Heparin plasma(n=5) 80-92% 86%

Linearity

The linearity of the kit was assayed by testing samples spiked with appropriate concentration of CD28 and their serial dilutions. The results were demonstrated by the percentage of calculated concentration to the expected.
Matrix 1:2 1:4 1:8 1:16
serum(n=5) 95-104% 87-96% 89-101% 82-90%
EDTA plasma(n=5) 91-98% 83-101% 87-98% 95-102%
Heparin plasma(n=5) 88-97% 86-102% 91-103% 89-97%