Hello all, Discovered this site when doing some reasearch looking for UOA options. I came across a thread asking about the two and it was suggested to give both a try and compare them side by side to help make a decision, but I couldn't find somewhere that had actually been done so I gave it a shot. I know that UOA is not the end all of engine health, but rather another card to have in your hand to paint a better picture as you do maintenance and checks. I apologize if some of this post is a little redundant or scatter brained, I found that I was remembering additional info that I wanted to include several times as I was typing and went back to add it. Both of these samples were obtained the last oil change I did on my 2011 Silverado 1500 LC9. I caught the oil from the drain stream after letting it drain for 15-20 seconds. I also called each company to ask some questions about the results to try and paint a better overall picture of each company. A little background on the use of my vehicle. I average approx. 4,500mi/yr, during the week it's main use is driving me to and from work, 1.5 mi each way. During the winter months it gets very cold up here in Buffalo and I use the remote starter to warm it up for 15-25 minutes, which is actually longer than it takes me to drive to work. There are some times where it's not driven on the weekend, I know it's less than ideal operating conditions, one of the reasons I wanted to start doing UOA to keep a little closer eye on it. I'm just trying to frame the conditions that the engine operates in so each companies reaction can be considered. I did not inform either of them of the conditions when I sent in the samples, I kind of wanted to see if they would be able to figure it out on their own. Both companies showed similar ppm of all tests across the board, neither state the margin of error for any of the tests, but I'm willing to bet that the differences were within the margin. They both deduced different aspects of the conditions. Blackstone got the idling, and OAI got the sample being obtained cold(the only time I can work outside is when the baby is napping, and the monitor don't got the range to cruise around the block, again less than ideal, but it is what it is) Oil Analyzers was the only one to pick up fuel in the sample. I had read that others have had issue with Blackstone's method of detection for fuel being inaccurate/low. So I figured I'd mention it, even though it wasn't a warning level, and is even further explained by the sample being taken cold. They also we're the only ones to pick up moisture in the oil, but they deduced that this was from the sample being obtained cold. I like that OAI includes the base number with their standard test barrage, where Blackstone costs an extra $10 I believe, I did not pay for it extra from Blackstone. I'm not trying to extend my OCI, I just want to get a better picture about the overall health of the engine. I called each company and asked about the high values of iron, as well as explaining some of the conditions that the engine operates under and asking if that would explain the values. Both companies were helpful, agreed that at the moment there's no red flags that jump out at them. And recommend continued monitoring in order to establish trend values to paint a better picture. Both companies were very easy and quick to get ahold of a lab tech. I know that a lot depends on the individual person that you just happen to be connected with in this area. But there's not much else for us as customers than to base our opinion on than our experience, so I figured I'd include my experience. It is not my intention to throw anyone under the bus. I did feel better after talking with the tech from OAI. The answers were much less vague/ambiguous, and seemed to have a more confident knowledge about their tests, how each test was done, and explaining what it means. I also asked about the comments being auto generated, because I had read that was an issue with OAI. He said that the computer comes up with the reactions to the values, but that the tech that generates your report chooses the order of them and the emphasis, and can edit them based on your particular engine and past tests. While I know that there will still be naysayers, I was happy with that explanation, and don't think that it's a negative against them. I also like the Mobile app that OAI has. I received the test results from both in an email. But it's nice to have the app to consolidate and organize everything. Especially if you decide to have multiple vehicles you want to keep track of. I told myself that I didn't want this to be a factor in choosing one or the other, the test itself is the important part, and the knowledge of the techs behind the company. Not the convenience of the presentation. Would love to hear everyone's thoughts and their experiences with these companies, or others that I haven't heard of, and hear why they prefer or choose the one that they use. This post ended up being much bigger than I initially intended, especially for my first post lol. So sorry if I posted in the wrong area or formatted it wrong, just wanted to share my (Limited) experience. Thank you for the read!