The lead time for the mouse IL-6 ELISA kit is too long. Is there any channel with stock available?

When you can't find the item in stock, consider borrowing an unopened plate of the same brand and catalog number from the lab next door, or first buy a domestic in-stock kit for parallel comparison. Take 6–10 samples and test them with the two kits separately, and see whether the trend and absolute concentration deviation fall within an acceptable range. If the deviation is large, wait for the original product; if the deviation is small, you can use the domestic kit to generate data first. This approach is suitable when time is tight, but you must note the detection system in the report to avoid being questioned.

For plasma testing, confirm the sample types compatible with the kit. It is best to have the agent provide spike recovery data for EDTA or heparin plasma. If not available, perform your own spike recovery at low, medium, and high levels using plasma. Heparin plasma sometimes shows high background or low recovery, while EDTA plasma is more stable. If sample collection is not yet complete, it is recommended to use a uniform anticoagulant for subsequent samples. If the price is not unreasonable, domestic in-stock kits are generally negotiable, but require a complete unopened set including standards; do not buy aliquoted products.

First, look for domestic first-tier distributors rather than ordering from brand official websites. UniV, Dakewe, Lianke, and Xinbosheng typically have some items in stock or in bonded warehouses. Clarify two points: whether they ship from a domestic warehouse and whether they can provide a tracking number. If delivery is within a week, try to arrange same-city courier or SF Express. When our lab had an urgent need, we asked a distributor to transfer stock, and it was shipped by SF Express the same day and arrived the next day. Don't just trust the "in stock" label on Taobao or platform pages—many are shipped directly from overseas, and the actual lead time is unpredictable.

Store samples at -80°C. In plasma, IL-6 generally does not degrade significantly within a few weeks in the short term, but it is more susceptible to repeated freeze-thaw cycles. If you have already aliquoted the samples, there should not be a major issue; if not, aliquot on ice before use and avoid repeatedly thawing the entire tube. In my personal experience, delaying cytokine testing by 2-4 weeks does not have a major effect on IL-6, provided that the plasma was centrifuged cleanly during processing and there is no hemolysis. You can first take a small amount of sample for a preliminary test; it is not necessary to discard all of them.