What are the approximate price ranges for domestic and imported ELISA kits? How should I choose when the budget is limited?

Domestic in-stock lead times are generally shorter than imported ones, commonly shipping within 1-2 weeks, but you should also ask the distributor whether cold chain access is available, as well as transit time and temperature records. If the budget is limited, you can first choose domestic manufacturers whose products have been cited in the literature and who can provide a CoA or trial size, and ask the sales representative to provide the test report for that lot and customer cases. Do not buy the full quantity right away; first buy 1 box and test 5-10 samples to check the standard curve linearity, background, and sample dilution linearity, then decide whether to restock. For the same target, try to order the same lot number and reserve enough standard to perform bridging between lots. If samples are precious, it is recommended to aliquot and freeze key samples for later repeat testing. In this way, even if the domestic kit is not very stable, you still have a fallback.

If you run 80 samples in duplicate, after deducting the standard curve, blank, and quality control wells from one 96-well plate, you can process roughly 30-40 samples, so at least two plates are needed. For imported R&D kits, the four to five thousand you mentioned is indeed common, but there is often a gap between list price and distributor transaction price, so you can ask two or three distributors to quote tax-inclusive and freight-inclusive prices and whether all components are included (standard, diluent, wash buffer, ELISA plate). The domestic range of eight hundred to two thousand is also common, but you need to clarify whether it is pre-coated or self-coated, whether the standard is sufficient for two curves, and whether low-value and high-value quality controls are provided. If the budget is tight, it is recommended to compare based on actual cost per sample rather than price per box, and especially note that some domestic kits have fewer components and require separate purchase of diluent or wash buffer.

Whether the inter-batch variation of domestic kits is acceptable must be verified by your own validation. It is recommended to first purchase two kits from the same lot, and complete 80 samples in one batch as much as possible to avoid restocking and lot changes midway. After arrival, first use 5-8 real serum samples plus high and low value quality controls to perform intra-assay replicates and next-day inter-assay replicates: calculate CV, back-calculate concentrations from the standard curve, spike recovery, and linear dilution. If high-value samples exceed the upper limit of quantification, re-dilution is required. IL-6 and TNF-alpha are usually very low in normal mouse serum, so confirm that the lower limit of quantification can cover the baseline values and post-stimulation peak values in your model. If the inter-batch CV and recovery rate are within the error range allowed by your project, and you are only performing between-group comparisons, many domestic kits can be acceptable; however, for publication or pharmacodynamic data, it is recommended to retain key samples for re-testing.