#415 ‒ AMA #91: Understanding lab testing: what blood work can and cannot tell you about your health and disease risk

View the Show Notes Page for This Episode https://peterattiamd.com/ama91/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=261109-pod-ama91&utm_content=261109-pod-ama91-podfeed Become a Member to Receive Exclusive Content https://peterattiamd.com/subscribe/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=261109-pod-ama91&utm_content=261109-pod-ama91-podfeed Sign Up to Receive Peter's Weekly Newsletter https://peterattiamd.com/newsletter/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=261109-pod-ama91&utm_content=261109-pod-ama91-podfeed In this "Ask Me Anything" (AMA) episode, Peter explores what laboratory testing can—and cannot—tell us about our health. Blood tests provide objective numbers and reference ranges, making them an appealing way to assess overall health. But their usefulness is far more nuanced than it may appear. Peter begins by explaining how to interpret lab results in the context of both lifespan and healthspan, emphasizing the importance of tracking changes over time rather than relying on isolated measurements. He then examines the strengths and limitations of blood testing for assessing risk across the major chronic diseases, including cardiovascular disease, metabolic dysfunction, cancer, and neurodegenerative disease. He explains what labs can reveal about organ health and where additional information from imaging, body composition, and functional testing is needed. The conversation also explores why more testing does not necessarily lead to better clinical decisions. Peter discusses the limitations of large direct-to-consumer testing panels and sophisticated measures such as lipid subfractionation and biological-age scores, particularly when the results lack clear clinical actionability. He also highlights the importance of physical function, cognitive performance, and emotional health—critical components of healthspan that cannot be adequately captured through blood work alone. Finally, Peter provides a practical framework for evaluating any laboratory test, understanding its limitations, and determining whether the results offer meaningful information that can guide decisions about health and longevity. If you're not a subscriber and are listening on a podcast player, you'll only be able to hear a preview of the AMA. If you're a subscriber, you can now listen to this full episode on your private RSS feed https://peterattiamd.com/members/private-podcast-feed/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=261109-pod-ama91&utm_content=261109-pod-ama91-podfeed or our website at the AMA #91 show notes page http://peterattiamd.com/ama91/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=261109-pod-ama91&utm_content=261109-pod-ama91-podfeed. If you are not a subscriber, you can learn more about the subscriber benefits here https://peterattiamd.com/subscribe/?utm_source=podcast-feed&utm_medium=referral&utm_campaign=261109-pod-ama91&utm_content=261109-pod-ama91-podfeed. We discuss: Why lab testing is insufficient to answer the question "Am I healthy?" [2:15]; Defining health through the lenses of lifespan, health span, and fundamental organ systems, and how labs can come up short [5:45]; The importance of longitudinal data, and the strengths and blind spots of labs for assessing cardiovascular disease risk [10:00]; Using labs to assess metabolic health, and the additional insights from body composition, behavior, and functional testing [18:45]; What blood tests and genetic testing can reveal about cancer detection and future cancer risk [23:00]; Assessing neurodegenerative disease risk through genetics, cardiometabolic markers, and emerging blood-based biomarkers [28:00]; What routine labs reveal about organ systems, and how to evaluate large direct-to-consumer testing panels [35:00]; Sophisticated tests that lack clinical actionability: lipid subfractionation, biological-age scores, and sleep scores [41:30]; Why labs provide limited insight into physical function, cognitive function, and emotional health [47:30]; A practical framework for interpreting any lab test, understanding its blind spots, and placing results in context [53:30]; and More. Connect With Peter on Twitter https://twitter.com/PeterAttiaMD, Instagram https://www.instagram.com/peterattiamd/, Facebook https://www.facebook.com/peterattiamd/ and YouTube https://www.youtube.com/channel/UC8kGsMa0LygSX9nkBcBH1Sg

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:10Dr. Peter Attia?

  Hey everyone, welcome to a sneak peek Ask Me Anything, or AMA, episode of the Drive Podcast. I'm your host, Peter Attia. At the end of this short episode, I'll explain how you can access the AMA episodes in full, along with a ton of other membership benefits we've created. Or you can learn more now by going to peterattiamd.com/subscribe. So without further delay, here's today's sneak peek of the Ask Me Anything episode. Welcome to Ask Me Anything AMA, episode 91. Today, we're going to talk about lab testing. Labs are often the first thing people reach for when they want an answer to probably

• 0:51Dr. Peter Attia?

  the most important question imaginable, which is, am I healthy? They're objective, numerical, and come with reference ranges. So it's easy to treat them as a report card on your entire health status. But that instinct kind of oversells what labs can actually do. Their real utility is actually a lot more nuanced than that. So today, we're going to walk through where lab testing is genuinely helpful, where it's useful but incomplete, and where it tells us very little, or frankly, nothing. And it gives you a framework for noticing the difference. So we're going to cover why people turn to labs to answer the am I healthy question, and what that question really means in the context of longevity, how to use blood

• 1:33Dr. Peter Attia?

  work for each of the major chronic disease states, cardiovascular disease, metabolic dysfunction, cancer, and neurodegeneration, and what labs are missing in each case, what labs can and can't reveal about the organ systems in our body, and why more tests doesn't necessarily mean more useful information, why large, direct-to-consumer panels and biological age scores can look sophisticated without necessarily changing a single clinical decision, how the picture changes when we shift from lifespan to health span, and why physical function, cognitive function, and emotional health mostly can't be captured in a blood draw. And we'll provide you with a practical set of questions to ask about

• 2:14Dr. Peter Attia?

  any lab test, so you'll know what it's actually telling you, and perhaps, more importantly, what it isn't. If you're a subscriber, and you want to watch the full video of this podcast, you can find it on the show notes page. And if you're not a subscriber, you can watch the sneak peek of this video on our YouTube page. So without further delay, I hope you enjoy AMA number 91. Peter, welcome to another AMA. How are you doing? Very well, thanks. Awesome. So today's AMA, we're going to focus on lab testing. And if you compile all the questions people send us, the vast majority of them will touch this topic at some level. Meaning, someone says, hey, I just got blood work done, and the result

• 2:57Dr. Peter Attia?

  of X was Y. What should I do? So I think it's not only a topic that is interesting and a lot of people care about, but it also seems like this is where people really focus on, you know, a report card of their health, in a way. And so I think what'd be helpful is when we start, is for you, when you work with patients, you're obviously reviewing labs with them often. And when you do it for the first time, you know, what do you hear from them? What do you hear that patients typically are hoping that these labs will tell them when you're going through that review? Well, I mean, I think people rarely say explicitly, hey, I just want to know if I'm healthy or not. I mean, I think more broadly, there's a belief, and over the years,

• 3:40Dr. Peter Attia?

  in anticipation of that, I've sort of preemptively addressed this on every first lab call. But the belief is that, hey, by the time we're done this exercise today, I'm going to know everything I need to know about my health. And obviously, you know, a subset of that, or at least subservient to that question, is I will know if I'm healthy, right? And again, it's a very understandable assumption to come in to a lab assessment with, because for the most part, when you've interacted with the healthcare system, the only routine maintenance things that tend to get done are lab testing. Now, of course, there's more than that. But we don't, we tend to think of imaging in a separate category. So obviously,

• 4:24Dr. Peter Attia?

  a woman who gets her mammogram every year would also consider that a part of her routine health maintenance. But for most people, when we interact with our doctors, we're doing so around lab tests. And again, they're objective, they're numerical, they have these reference ranges. I mean, all of these things about them make them feel like they should be complete. And I think there's another thing, which is that if you don't fall outside of a reference range, and therefore, nothing is getting flagged, I think people sort of assume, hey, all systems are go. You know, the check engine light isn't coming on, so everything is, is okay. And I would say that that view has probably been amplified over

• 5:06Dr. Peter Attia?

  the past few years, because there is really no shortage of direct-to-consumer testing products out there. And that's kind of, I think, doubled down on that belief system, which is, hey, this is, this is the thing you need to know. And if you, if you buy our D to C product that will check your labs, and frankly, even, even test lots of labs, we're going to have the solution to every, to every problem. And so I usually just start by explaining where I think the labs are valuable, but also where their blind spots are. And I think that's a, that's, that's a, that's an important discussion to have, so that at the end of the lab discussion, I usually end up saying something to the effect of, look, we will know roughly a third of what we care to know about you, maybe,

• 5:51Dr. Peter Attia?

  maybe, maybe a bit less, maybe 25%. And that's a very important 25%, but we have a lot of work to do to really kind of get under the hood of truly understanding risk across everything that we care about. And that's something we're going to dive into much more detail here today's AMA. But I think what may be helpful is kind of stepping back, you ask the question, you know, are you healthy, right? And that's ultimately what people care about and want to know. And so when you're trying to understand the answer to that question for your patients, you know, how do you go about that? What are you, what are you looking at? And what are you truly trying to understand around that core question of, am I healthy? I mean, look, I think you have to start with defining what that means. And I think

• 6:36Dr. Peter Attia?

  there are different ways to define that. If you're talking to a patient who has just finished chemotherapy for cancer, then the definition really probably should center around that, right? It should be, am I NED? NED means no evidence of disease. So has the chemotherapy worked? Is the cancer, for all intents and purposes, gone? Are my blood counts back to normal? Because chemotherapy often wreaks havoc on the hematopoietic system. And that frankly, might be all you care about, right? Am I not anemic? Have my white cells come back? And am I free of cancer? And that, that would constitute the definition of am I healthy at the moment. And so in our context, in our practice, which I actually

• 7:19Dr. Peter Attia?

  think reflects what many people are hoping to achieve when they, when they think through this question, we are really trying to think about it through the lens of what are the threats to longevity? And again, longevity has this very, at least in our view, pretty clear definition, that's, that's pretty straightforward, right? Which is, it's the, it's the product of both lifespan and health span. And therefore, if you're, if you're in pursuit of better longevity, what that's saying is, I want to live longer, or I want to live as long as possible, in as high a state of health as possible. And not having one of those things is insufficient. So living a long time in poor health, that's, that's

• 8:01Dr. Peter Attia?

  not optimal. And having a short life in high health is also not optimal. So we want both of those things. And we frame it through the lens of, what are the impediments to those things? And it's actually a relatively finite number of things. So on the lifespan side of things, the impediments are the things that will shorten your life. So that is cardiovascular disease, cancer, neurodegenerative and dementing diseases, metabolic disease, accidental deaths, those are really the big ones. Now, of course, there are also organ-specific diseases and things like that that can fit in there. And we would always address those when relevant. So, you know, a person can also die from chronic obstructive pulmonary disease if

• 8:46Dr. Peter Attia?

  they have a longstanding history of smoking, kidney disease, liver disease that is unrelated to metabolic disease, et cetera. So, so there are other things in there. But you're capturing most of it through what we just described. And then on the health span side of things, we're really talking about physical health. And so that's, you know, freedom from pain, strength, endurance, excellent mobility, basically, the ability to do anything you want physically. And different people will have a different threshold, of course. So some people will have very high aspirations there, and others will have modest aspirations, and therefore, they'll have a different standard for what constitutes healthy. Then there's a cognitive component to that, which is the ability to, to engage with your, with your

• 9:31Dr. Peter Attia?

  brain, right? So this is everything from processing speed, and short-term memory, and long-term memory, executive function, all of those things. And then there's an emotional component, which is, again, made up of many things, but it includes sense of purpose, happiness, strength of relationships, emotional resilience, high distress tolerance, all of those things. And as we go through this exercise, we feel that health constitutes everything I just talked about. And then we talk about, how does the lab result help those things? Is it informing those things? And if so, great. And if not, then do we have another way that we can look at those things? And so, before we kind of dive into labs, as it relates to each of those kind

• 10:16Dr. Peter Attia?

  of major diseases and categories you laid out, I think from a high level, how do you think about, like, a single snapshot of someone's lab? So if you're meeting with a patient for the first time, and you have their labs from the week prior, right? How informative is that compared to if you have the labs from a week prior, as well as like a longer history of all the random times that they went to the doctor?

• 10:43Dr. Peter Attia?

  Well, I think there are a couple of things embedded within that. The first is reliability of a lab. So if you only have a snapshot, if I only saw your labs, Nick, from today or last week, and I had no access to anything else, it would be really difficult to make a decision, even in the context of something that was abnormal. Because I truly don't know if it is abnormal, or if it's just actually a laboratory error. So you always have to have that in the back of your mind. And that's much easier to evaluate when you have longitudinal data. Furthermore, even if I know that it is aberrant,

• 11:28Dr. Peter Attia?

  pardon me, not aberrant, right? If I know that, hey, that result is actually what it says it is, I don't necessarily know how long it's been abnormal. And in some cases, that might matter. So I'll give you an example. If I see that your C reactive protein is three, and if this is a highly sensitive C reactive protein, that would be quite elevated. And then let's assume I just immediately repeated the test, and lo and behold, it was three, not a lab error. Okay. But is it just three this week? I mean, maybe you're sick. Maybe you were vaccinated two weeks ago, and this is still some lingering level, and it's coming back down, but it was 42 weeks ago. But your baseline is 0.5.

• 12:10Dr. Peter Attia?

  I can't figure out if this is sort of chronic inflammation, or if it's reactive, if it's going up, if it's going down. So it would be difficult for me to sort of weigh in and say that we're going to implement this playbook that we typically implement for people that have high inflammation. The same, I think, would be true for something like ApoB or LDL cholesterol. So if your LDL cholesterol is, let's say it's 160 mg per deciliter, that's very, very high, right? That would put you above the 80th percentile. If that's just that high because you've gone on a diet in the past three months that has you mainlining saturated fat, and your ApoB and LDL-C have gone up, that's kind of a different situation

• 12:55Dr. Peter Attia?

  than if it's been that high your whole life, which might actually suggest you have a genetic condition that's driving that. So I think longitudinal data are valuable, but you also have to work with what you have. There are some people who come in with very little longitudinal data, and you still have to make decisions based on the information you have. Obviously, there are certain things that you don't need to check more than once, LP little a, ApoE, or any other genetic test, assuming that the answer you got is correct and the lab was done. So I don't know. Hopefully, that answers your question. It's a bit of both. No, for sure. And I think it will be helpful now to kind of go through the major chronic diseases one by one that you laid out earlier, and just talk about, okay, where are labs helpful?

• 13:40Dr. Peter Attia?

  And where do they kind of leave a picture still unpainted? So let's start with the biggest killer, cardiovascular disease. So what do labs tell us? And how helpful are they in understanding someone's risk of this disease? Thank you for listening to today's sneak peek AMA episode of The Drive. If you're interested in hearing the complete version of this AMA, you'll want to become a premium member. It's extremely important to me to provide all of this content without relying on paid ads. To do this, our work is made entirely possible by our members. And in return, we offer exclusive, member-only content and benefits above and beyond what is available for free. So if you want to take your knowledge of this space to the next level, it's our goal to ensure members get back

• 14:25Dr. Peter Attia?

  much more than the price of the subscription. Premium membership includes several benefits. First, comprehensive podcast show notes that detail every topic, paper, person, and thing that we discuss in each episode. And the word on the street is, nobody's show notes rival ours. Second, monthly Ask Me Anything or AMA episodes. These episodes are comprised of detailed responses to subscriber questions typically focused on a single topic and are designed to offer a great deal of clarity and detail on topics of special interest to our members. You'll also get access to the show notes for these episodes, of course. Third, delivery of our premium newsletter, which is put together by our dedicated team of research analysts.

• 15:08Dr. Peter Attia?

  This newsletter covers a wide range of topics related to longevity and provides much more detail than our free weekly newsletter. Fourth, access to our private podcast feed that provides you with access to every episode, including AMAs sans the spiel you're listening to now and in your regular podcast feed. Fifth, the Qualies, an additional member-only podcast we put together that serves as a highlight reel featuring the best excerpts from previous episodes of The Drive. This is a great way to catch up on previous episodes without having to go back and listen to each one of them. And finally, other benefits that are added along the way. If you want to learn more and access these member-only benefits,

• 15:50Dr. Peter Attia?

  you can head over to peterattiamd.com/subscribe. You can also find me on YouTube, Instagram, and Twitter, all with the handle PeterAtiaMD. You can also leave us a review on Apple Podcasts or whatever podcast player you use. This podcast is for general informational purposes only and does not constitute the practice of medicine, nursing, or other professional healthcare services, including the giving of medical advice. No doctor-patient relationship is formed. The use of this information and the materials linked to this podcast is at the user's own risk. The content on this podcast is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard or delay

• 16:33Dr. Peter Attia?

  in obtaining medical advice from any medical condition they have, and they should seek the assistance of their healthcare professionals for any such conditions. Finally, I take all conflicts of interest very seriously. For all of my disclosures and the companies I invest in or advise, please visit peterattiamd.com/about, where I keep an up-to-date and active list of all disclosures.