Shanghai ancient flower talk about the use of ELISA kit should pay attention!
ELISA methods are widely used in various antigen and antibody assays. However, there are many influencing factors in the ELISA assay, and there are certain technical requirements in the operation. In addition to the normal reaction, sometimes some wrong results are often found in the detection process. The main causes of ELISA error results are: 1 specimen factor; 2 reagent factor; 3 operational factors. The following are some of the problems in the common ELISA process.
Sample dilution
The enzyme-linked immunoreactivity is a highly sensitive reaction. If the serum is not diluted, it will inevitably produce a strong non-specific reaction and a false positive.
2. Kit balance
All reagents and strips in the kit should be equilibrated to room temperature (about 25 ° C) before the test, generally at room temperature for 20 to 30 minutes. Too short a balance time will result in insufficient reagent mixing, a relatively short incubation time, and insufficient ELISA. The room temperature is low in winter, and the kit can be placed in a 37 ° C incubator for 20 minutes.
3. Mixing samples and reagents
Samples before and after dilution must be thoroughly mixed. All reagents should be shaken before loading to ensure uniformity of the test.
4. Sample loading
In the current ELISA kit, there is necessarily a step of adding a sample using a micropipette. The key point of attention is: do not add too fast, avoid adding to the upper part of the hole wall, do not spill and create bubbles. Loading too fast, can not guarantee the accuracy and uniformity of micro-dosing
5. Incubation
Incubation is one of the most critical factors influencing the success or failure of an assay in an ELISA assay.
6. Wash the board
Solid phase immunoassay is a heterogeneous immunoassay technique in which the antigen or antibody that specifically binds to the solid phase is separated from the non-specific components adsorbed during the reaction incubation to ensure the specificity of the ELISA assay. Sex.
7. Edge effect
In the ELISA assay using a 96-well plate, an "edge effect" is often found, that is, the peripheral pores are darker than the central pores. Studies have shown that thermodynamic gradients in incubation may be the root cause. Polystyrene itself is a poor thermal conductor. In the laboratory routine ELISA, the plate is placed in a 37 ° C incubator from room temperature (usually around 25 ° C). When the plate is also warmed, it may be between the peripheral hole and the center hole. There is a thermodynamic gradient.
8. Color development
Color control must be controlled, according to the kit instructions. In general, the color development time is too short, and the result is low; the color development time is too long, the blank is increased, or the non-specific color development is increased.
9. Colorimetric
Colorimetry should pay attention to the choice of wavelength. TMB is used as a substrate and an OPD-based kit is used. The former has a colorimetric wavelength of 450 nm and the latter has a wavelength of 492 nm. The filter needs to be replaced at any time according to requirements. Therefore, the problem of misuse of the filter is apt to occur.
Second, the problem of single-wavelength or dual-wavelength colorimetric selection. The so-called single-wavelength colorimetric is usually measured by a colorimetric measurement such as 450 nm or 492 nm for absorption of color, while the dual-wavelength two-color measurement is performed once at a sensitive wavelength such as 450 nm and a non-sensitive wavelength such as 630 nm. The absorbance measurement value of the upper and lower sides of the sensitive wave is the sum of the absorbance of the specific coloration of the enzyme reaction and the absorbance caused by the fingerprints, scratches, dust and the like on the plate hole; the wavelength is changed to a certain value when the non-sensitive wavelength is measured, The absorbance value of the sample for measuring the specific color of the enzyme reaction is zero, and the absorbance measured at this time is the absorbance value of the dirt.
A pet Strap Dog Harnessis is equipment consisting of straps of webbing that loop nearly around-that fasten together using side release buckles-the torso of an animal.
These strap dog harnesses generally are made to have both a strap on the chest in front of the forelimbs, and a strap around the torso behind the forelimbs, with straps in between connecting these two. Having a D-ring suitable for (pet tags and) a leash to clip to, they are most often used to restrain an animal, but dogs also particularly wear them to assist a person with a disability or haul people and items. There is also the lifting harness for dogs with disabilities, covered in this article.
Some come in different sizes, although many are size-adjustable with tri-glide slides to loosen or shorten the straps` length. The straps may come in a range of different colors, and some have reflective coating.
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