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As starting dilution in HS ELISA, with all three items, we recommend 1/5.000 (200 ng/ml). This dilution will be close to saturating dilution in many HS ELISA systems that with good antibodies will yield close to maximum sensitivity. In some rapid ELISAs more concentrated conjugates (up to 1/2.000 but unlikely more concentrated than 500 ng/ml) can be applied within the same 30-min. or shortened 20-15-min. incubation time. In practice, however, developmental situation with SA-PolyHRP does frequently look different. Many researchers, driven by "pressure" of high backgrounds, tend to dilute SA-PolyHRP very strongly applying conjugates at working strength dilutions down to 1:10.000 - 1:20.000 - 1:40.000. They of course lose some sensitivity but at the same time obtain more "comfortable" situation with backgrounds and gain advantage of having on the total very economical reagent consumption levels. This however creates another difficulty when working with stock PolyHRP conjugate solution. Making daily working dilutions necessitates dispensing minor microliter volumes. Practically, working strength conjugate dilution in such cases must often be produced through executing intermediate dilution(s). This makes daily developmental work with PolyHRP stock solution either less precise and less reproducible or less economical, or quite precise but more cumbersome and, again, less economical. Suggestion to use SA-PolyHRP Stabilizers addresses this experimental circumstance. Stabilizers give the possibility of creating intermediate conjugate dilutions that will be long time stable at regular storage (+2°C/+8°C) and handling/working (+18°C/+25°C) temperature regiments. Preparing stable intermediate formulation in the range e.g. 500X - 10X of final working strength - for further making daily working dilutions respectively 1/500 - 1/10 - will make developmental work with PolyHRP much more convenient, more precise and more economic. That is why we currently offer PolyHRP also in pre-diluted stable at +4°C/+25°C format. Three different versions (50, 10 & 2 µg/ml) of SA-PolyHRP are available within convenient choice of flexible packaging in diverse sizes. This option will increase level of precision and overall reproducibility in developmental work with PolyHRP. Working with stable pre-diluted PolyHRP conjugates is strongly recommended when running at least primary development. |