In response to the blue-closure tube shortage, I [Geo] contacted several colleagues who prepare or who used to prepare their own 3.2% [and pre-2000, 3.8%] sodium citrate solution for hemostasis specimens. Nearly all said that, like your grandmother, the recipe was just in their heads. Dr. Emanuel Favaloro, Sydney, NSW, dug into his laboratory archives and sent formulas and instructions, which I have paraphrased in the attached document. I have yet to find peer-review publications giving formulas or efficacy data, so I’m hoping there is someone among our participants who has additional official documentation. Meanwhile, thanks to Dennis Ernst, Dr. Larry Brace, Bob Gosselin, and Dr. Favaloro for their responses.