four labs, one blinded pool, and the cleanest result yet

The largest pooled submission the room has organised went out blinded to four laboratories, covering material from six suppliers bought by nine different members. The organisation was competent, which after three years is almost the most notable thing about it. The results were less dramatic than the 2025 pools and considerably more useful, because the method reporting was complete.

• Janoshik, Medutest, PeptideMeter and VendorInvestigate all appear in the writeup, three for analysis and one for supplier and domain checks.
• Content figures clustered far more tightly than in the 2025 pools, which the writeup attributes to sample handling rather than to any supplier improving.
• Chinese Peptide Company, Wuhan Wansheng and Zhuhai Kerui material all came back within a few percent of label on content.
• One source produced a single low outlier that was not reproduced on a second lot, and the room declined to draw any conclusion from it.
• The chain-of-custody limits were stated in the first paragraph as usual, including how long samples sat in domestic fridges.
• blind_submit published the code sheet after the fact so that anybody can check the blinding held.