This post is probably not actually about this great new review. I'm just leaving a link about it here because I'm reasonably sure one of the peer reviewers put this team through the wringer. Is that a thing? Why would it be related? I don't know, but it's a great and valuable review! 👮
This post is about ALLLLLLLL the ways we can now go way way beyond those top 300-800 most abundant proteins in human circulating blood liquids. Definitely not all, I can't keep up! Edit: Definitely not all. Geez. The last paper cited below mentions 4 other ones! Okay, maybe later edits will mean adding to this and not just correcting.
For anyone who has never ran human plasma or serum and is excited to do this by LCMS, do I have some crazy stuff to tell you. If you put that on an S-Trap or something else where you're used to getting 4,000 - 10,000 proteins, you'll probably get about 500 protein groups on your first try. If you've got today's most badass $1M thingamabob you might get 1,000. Maybe. Probably 800 is your max. And that's it. Shameless plug, for the Equalizer plasma proteomic standard, we had a poster at US HUPO where 8 labs contributed data. An Astral Zoom running a 45 minute gradient won't get you 2x more proteins (620) than an LTQ Velos from 2011. The dynamic range is just
However...if you use new magic techniques that not one single person on planet earth can explain to any other person without the made up concept of a "protein corona" (I blame the Broad for this made up terminology -it's not worse than "the mobile proton model"), you can now dig deeper following chemical or physical enrichments.
Let's count the ways! I'm currently aware of these -
SEER Proteograph
SP3
Ceres
Mag-Net
PCA and PCA-N
...which is already a lot....
Geez, and there is a new one I don't think anyone has published on yet. P2 from Biognosys. I may lump it in with SP3 based below until I find out I'm totally wrong.
Let's inaccurately compare all of them!
SEER - possibly the originator of this whole field, however, it appears that most attempts to claim this legally as something they've developed haven't gone super well. Some may still be in progress, but at least 2 have been initially thrown out of court.
Pros - probably the best data out of anything we've seen. It is one thing if 50 of the best mass spectrometrists in the country at Cedars Sinai can get 6,000 proteins in plasma. However, I'm hearing that anyone who buys the Proteograph system and reagents for their own lab and runs it is getting comparable results.
Cons - Expensive. O-Link expensive? No. Illumina Protein Prep expensive? Absolutely not. Is the data far more valuable than either of those technologies? Yes, and particulary in the case of the Illumina solution. In my opinion, there is no greater misuse of funds in 2026 than running the Illumina Protein Prep for more money if you could run the SEER Proteograph and get actual quantification data. The fact that O-Link is quantitative and can theoretically scale to far higher levels and eventually be cheaper is a little more defensible. However, in the context of what people are used to paying for LCMS it is a lot of money for a sample prep, and that has allowed other technologies to propagate.
SP3 based - these are a magnetic bead based prep that appears to have a solid number of users. It looks less expensive than the proteograph, but I think all 5 of the published comparisons have found it to have inferior results. It should also be noted that this prep requires that your soluble blood proteins (plasma/serum, whatever) is prepared by the clinicians or phlebotomists in a very specific way. If you DO NOT have control over this, you should very very carefully read those instructions. You can't just put any blood plasma/serum thing in it from any old biobank into this workflow and expect success. It should also be noted that I have heard from 4 separate people that sometimes you end up with magnetic beads clogging weird things in your nanoLCs. There is a moderately expensive and otherwise indestructible porcelain needle on the EvoSeps and you should have spares on hand when using these magnetic beads.
The one I've heard most about is the PreOmics one which is called iST-BC3 (which, to be fair is the one that has the very specific limitations on what fluids it is fully compatible with) but I suspect that the new Biognosys P2 one is closely related to this. I think they're both largely or entirely owned by the same company now? It would be smart to consolidate methods if that is the ase.
Pros - mid-tier cost? Commercial support kits still mean commercial support teams (people to complain to and get help from!) My impression is that you're talking 1/2 to 1/3 the price of a Proteograph prep. So if SEER is $300-$400 or something, this is closer to $100? I'm sure it all depends on scale, etc,.
Cons? - Might not be compatible with every type of human derived blood proteins.
Ceres - is some sort of a porous thing amabob and they're making a splash on the scene right now by being willing to send you a free kit to get going. If you're struggling I hear you can get an applications scientist on site to walk you through it. Our first attempt with a kit involved going away from the established workflow and the results were still an improvement, but below the expectations of Ceres and I think someone is coming to help us out later this summer. Ceres got a big endorsement from one of the best proteomics core labs in the country. The total plasma proteomics workflow - including enrichment and analysis - is advertised as considerably less than an enrichment by Proteograph. That seems to indicate a very cost-effective enrichment. They aren't advertising Proteograph level depth, but expecting 3k proteins in plasma was science fiction a couple of years ago.
Pros - Solid endorsement and good numbers, and US based support team. Sounds very affordable. Tens of dollars?
Cons - Might not be the best numbers out there yet, and there isn't nearly as much published data for it out there.
Mag-Net - wow, this one is confusing and controversial for one reason or another that I don't want to go into. I've heard that it might be due to how one group prepared the plasma without following the published instructions. Here is a good comparison.
Ugh. This paper points out 3 other enrichment kits that I didn't even know about! Okay, maybe I need to add to this one later. Okay, well, that's where there is a link here. These authors (who I think are completely unrelated to the Mag-Net inventors) report 4500 protein groups from plasma at "a remarkably low total cost of just a few dollars per sample"
Their words, not mine.
Pros - Very low cost, depending on how you do it. One core facility said you're talking about $5 -$10 in beads depending on where you get them and scale.
Cons - Might still be some controversy on it, but an increasing body of work suggests that it works just fine. If you do want to get some support on the workflow, this might be the central workflow endorsed by EvoSep. Maybe they'll have kits?
Perchloric acid (PC / PCA / PCA-N)
If you want to avoid particles entirely and just want a quick step with a weird acid or two, this is interesting. I've personally tried PCA-N and I found the results kind of -meh, but I have rarely done a great job of a new sample prep in my first attempt. PCA-N is the easier one of the two, you don't need a filter thing. You neutralize out the acid with NaOH or something and then you go right into your workflow. Perchloric acid is cheap and NaOH is virtually free at the amounts used here. It is worth noting, I think, that a group has recently reported no significant increase in the proteome when plasma was depleted of platelets with high speed centrifugation, so the method might be more controversial than you'd guess.
Pros - Almost no cost or time addition to prep. Add acid, pellet, neutralize. Filter if you're doing the original prep (with reusable filter things I don't fully understand).
Cons - Probably the least improvement in coverage. I think in the inventor's own studies neat plasma came in at 500-800 proteins per sample and PC and PCA-N got you to 1,000 - 1,500 protein groups. An improvement? Yes. Fast? Yes. Competitive with all the other stuff in terms of coverage? Doesn't sound like it. But a PCA-N study is coming that is 50,000 samples...so even a $20 prep kit is a lot of money. Is that $1M?? Extra on top of everything else? Ouch. So if you get some acid and NaOH from a pool store and it's virtually $0 to do that step? 1,500 proteins for no additional cost or $1M for 3,000 proteins will make a difference in a lot of studies.
Okay, this was helpful for me to type out. And then arranging them the way I did by descending cost, which does, with possibly the exception of Mag-Net, depending on which paper you believe, seems to also lead to decreasing relative coverage.
If there is a take-away here, every single one of these will give you more coverage than a neat digest of human plasma. You're looking at doubling proteins at an absolute minimum (probably) to getting 10x or 20x more protein groups. Every single one of them will provide quantitative data. Which is something you can not get from Illumina Protein Prep or SomaScan. If you actually want to know how much of each protein is present, then that's a no brainer, and every one is less expensive than that technology. Depending on which O-Link kit, etc., that you use, your scaling, etc., it's probably close to the cost of doing SEER, and I think that Proteograph will be - in almost every possible situation - the less expensive option than O-Link deep unbiased stuff. Sure, maybe if you're doing a million samples Thermo will cut you a break, but you still aren't getting those million samples back for a year or four, I don't care where you send it. Although new preps are rumored that might be able to get up into the 1e5 samples per year if nothing breaks and you run a prep every single calendar day. Nothing is going to get you to 1e6 without buildings full of robots. Who has that much (good) plasma anyway?

