Description
Enzyme immunoassay for the quantitative determination of Serum Amyloid A (SAA) in human serum, plasma, and other body fluids. Quality controls are included with the kit. Developed and manufactured in Europe by PromedeusLab.
Summary
Serum amyloid A (SAA) is a highly sensitive acute phase reactant that has been linked to inflammatory diseases, both infectious and non-infectious origin. SAA is an apolipoprotein that interacts with HDL, promotes the accumulation of leukocytes at the site of inflammation and the adhesion of platelets, and participates in the removal of damaged cell membranes. The acute phase SAAs (SAA1, SAA2) are transcriptionally regulated in hepatocytes by a variety of inflammatory cytokines, and they can transiently increase > 1000-fold. The combination of SAA, PCT, and CRP can improve the differential diagnosis of early bacterial and viral infections. Several studies indicated that SAA allows monitoring of disease activity in various inflammatory rheumatic diseases and autoinflammatory diseases, including SLE, amyloidosis, or rheumatoid arthritis. SAA also shows potential as a biomarker for risk prediction of coronary heart disease, the prognosis of tumor patients, and observation of transplant rejection.
Other Names
Serum amyloid A-1 protein, SAA1, Amyloid protein A, UniProtKB# P0DJI8.
Principle of Method
The microtiter plate is coated with the antibody specifically binding the Serum amyloid A (SAA1 and SAA2). The human serum or plasma is incubated in the plate with the capture antibody.
The specimen is washed out and the specifically bound protein is incubated with biotin-labelled detection antibody. Following another washing step, Streptavidin-HRP conjugate is added into the well. Unbound reagent is then washed out. Horseradish peroxidase (HRP) bound in the complex reacts with the chromogenic substrate (TMB) creating the blue colour. The reaction is stopped by addition of STOP solution (H2SO4).
The absorbance values are measured at 450 nm (optionally 450/630 nm) and are proportional to the concentration of SAA in the specimen. The concentration of SAA in unknown samples is determined from the calibration curve which is created by plotting the absorbance values against the standard concentration values.
Sample Types
Serum, Plasma, Other Body Fluids
Typical Standard Curve
Assay Range: 6.25 ng/mL - 200 ng/mL
Sensitivity
The limit of detection, defined as a concentration of human SAA giving absorbance higher than absorbance of blank + 3 standard deviations, is better than 1.56 ng/mL of sample.
Precision
Intra-Assay
| Test sample | Mean (µg/mL) | SD | CV |
| 1 |
15.0 |
1.4 |
9% |
| 2 |
0.9 |
0.1 |
10% |
Inter-Assay (Run-to-Run)
| Test sample | Mean (µg/mL) | SD | CV |
| 1 |
4.0 |
0.2 |
4% |
| 2 |
1.2 |
0.04 |
3% |
Accuracy
Dilution Linearity:
| Test sample | Dilution |
Measured Concentration (µg/mL) |
Expected Concentration (µg/mL) |
Yield |
| 1 |
4.6 |
- | - | |
| 1 | 2x | 2.4 |
2.3 |
103% |
| 1 | 4x | 1.4 |
1.1 |
119% |
| 1 | 8x | 0.7 |
0.6 |
117% |
| 2 |
10.8 |
- |
- | |
| 2 | 2x | 5.3 |
5.4 |
98% |
| 2 | 4x | 2.8 |
2.7 |
104% |
| 2 | 8x | 1.6 |
1.4 |
120% |
Spiking Recovery:
| Test sample | Spike (ng/mL) |
Measured Concentration (µg/mL) |
Expected Concentration (µg/mL) |
Yield |
| 1 |
- | 1.1 |
- | - |
| 1 | 2.5 |
3.2 |
3.6 |
89% |
| 1 | 1.3 |
2.2 |
2.3 |
94% |
| 1 | 0.6 |
1.7 |
1.7 |
102% |
Storage
The kit must be stored at 2–8 °C. The opened components can be stored for one week at 2–8 °C.
Usage
This assay is for in vitro research use only and is not for use in diagnostic procedures.
Resources
Ilex Life Sciences LLC is an authorized distributor of PromedeusLab.