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It’s an overcast Saturday morning when I give my 12th vial of blood for testing in six weeks. It’s my 24th this year. At this point, I feel like a pro. I schedule these blood draws first thing in the morning so I don’t get hangry, download the requisition papers ahead of time, avoid strenuous exercise for the 24 hours prior, and make sure to drink a glass of water beforehand so my teeny veins are easier for the phlebotomist to find.

In fairness, 12 of the 24 vials were ordered by my doctor to monitor ongoing treatment for a few metabolic issues. Eight were to feed my experimental digital twin. The last four are to test an app called Death Clock, which estimates when you’ll die based on your current health. Currently, the app says I’m going to die at 97 years old on Friday, October 5th, 2085.

For greatest accuracy, and to calculate my biological age, Death Clock offers a “free” blood panel with its $69 annual subscription. The app also offers various other optional, upsell panels recommended based on the health history you upload during onboarding. It suggested that I add on tests for thyroid function, heart and artery health, and liver function. On top of the blood panels, the app also recommended I try a continuous glucose monitor, buy a smart scale, buy a blood pressure monitor, get a professional VO2 max evaluation, schedule a liver ultrasound, screen for cervical cancer, start taking daily creatine monohydrate, schedule an annual full-body skin cancer exam, get a baseline coronary CT angiography, consider getting APOE testing for Alzheimer’s risk, and get a colonoscopy.

I was getting a vampiric promise of longevity. My blood was the roadmap to a long life. If I did everything the app’s “life lab” proposed, I could get an extra 17 years, dying at the ripe old age of 114 on September 12th, 2102.

Even so, watching my blood flow into yet another test tube, I thought of my parents. Blood is more than just a mix of plasma, iron, water, and nutrients. Metaphorically, it’s also a history of the family that came before you — and sometimes, though not always, clues to how they died.

Death Clock is a provocative name, but it’s hardly alone in wanting my blood. Oura and Whoop have already added partnerships with Quest Diagnostics, so their users can hand over their blood too. Google recently announced an integration with Function Health, a startup that makes it easy for people to order these kinds of lab tests. When Apple’s new Health app launches, that too will come with a Quest Diagnostics partnership. Blood is in, and more of these partnerships are undoubtedly on the way.

It’s not hard to guess why. Blood contains data — the thing that keeps health tech companies fed. In this age of personalized tech, what could be more personal than the stuff literally flowing through your veins? But as with any highly valuable, highly private data source, the user has to get something equally valuable in return. Right now, that seems to be a vague promise to live longer.

“The reality is life is precious, life is short, and we’re all going to die. The question is when, and I think culturally, we are in denial about death,” Brent Franson, founder and CEO of Death Clock, tells me. “Our view is we want to shake people and say, ‘Hey, the only thing that matters most in your life is whether or not you exist,’ and you want to take your health seriously so you can exist as long as possible.”

Franson says that to help people understand their own health and the changes they need to make, they have to know what’s going on in their bodies — that’s where the blood comes in. It feels like a hyper-literal take on the idea of looking inside oneself to find the answers to life.

It’s an alluring premise, but there’s a limit to what any one person can learn from any quantity of blood. Later in our conversation, Franson acknowledged that the greatest predictor of longevity is socioeconomic status. The rich live longer because they can afford better healthcare — and your blood says nothing about what your income bracket will be.

Those limits are sobering to witness firsthand. In April 2021, I got a phone call from my cousin in the middle of the night. My mom was struggling to breathe and had been rushed to the hospital. Something had been wrong with her for a while. Her speech had been slurred for a whole month, and she was struggling with phlegm that just wouldn’t go away. My mom insisted it was a stubborn cold. This cousin, a doctor, suspected my mom had a series of mini strokes and was now suffering from a potential combination of both a stroke and heart attack — a cardiocerebral infarction.

In the ER, my mom loudly protested that everyone was worried over nothing. Her father had lived to 101. Her mother was alive and doing well at 94. Her blood, our family blood, was destined for a long life, and we had no history of cardiovascular issues. (Never mind that my uncle had nearly died from a stroke the year prior.) She yelled at the top of her lungs that at 72, she was entirely too young to die.

The doctors didn’t find what was wrong with her that night. Over the next few months, we ran her through a gauntlet of tests, many of which involved blood draws and machines of all types. It turned out, my cousin was also wrong. My mom didn’t have a mini stroke and her cardiovascular function was perfectly fine. Instead, she died six months later from spontaneous bulbar amyotrophic lateral sclerosis, which has nothing to do with blood. It was in her body that April, but no blood test would’ve found it. ALS wasn’t in our family history — and as genetic testing later revealed, she didn’t carry the gene for it either. There was nothing she could’ve done to prevent it.

The other proposition is that running your blood through a health tech app’s algorithm and AI chatbots will tell you more about yourself. It’s presented as a democratizing move that empowers you to take action outside of the 15 minutes you might get with a doctor — or at the very least, helps you to make the most of an appointment.

I’ve uploaded my various blood tests to multiple apps, asking their accompanying AI chatbots to analyze my data. The big-picture interpretations are similar. My tests invariably point to an inflamed but improving liver. I had high cholesterol, but medication seems to be working. My cardiovascular labs have begun to look pretty optimal, according to every app. The combination of good fasting glucose and HbA1c alongside improving but mildly elevated fasting insulin suggests I have “managed” insulin resistance. In other words, I have learned that going to the doctor and addressing my myriad metabolic issues is working. I could have told you that without any of this extra data.

I’ve also learned that doctors, health tech features, and AI can look at the same tests and arrive at different conclusions. For instance, absolutely no one agrees about my most recent fasting insulin. I’ve been told it’s everything from normal to borderline high or high. What should I do? Do I need to do anything? I don’t know, because the advice is all over the place.

This type of mixed signaling leads to one of two outcomes. You could become a Bryan Johnson type, where you get 15 vials of blood drawn at once and sell your blood-testing protocol as a product. You could obsess over every tiny change. Or you could be like me and find this thinly disguised datamining expedition mainly repackages things you already know.

“Doctors don’t order these 150 biomarker panels like Function Health, and they don’t do it for a good reason. There’s a high false-positive risk in doing that many tests, especially on somebody who’s asymptomatic for most of the tests. It creates a lot of confusion and annoyance, I think, for existing primary care physicians,” says Franson.

When I point out that Death Clock also offers an extensive range of blood tests, he says the difference is the app takes a more middle-of-the-road approach. The app only covers a basic panel in the subscription — the rest are à la carte options depending on an individual’s health needs. Same as a doctor would do, he says.

Then what’s the point?

“What we want to be tomorrow is a full replacement for primary care as it relates to preventive health,” Franson explains, saying that patients should still go to doctors for scenarios like injuries or surgeries. His vision is to provide a sort of telehealth guidance for everyday lifestyle interventions and routine screening procedures.

“It’s kind of a Death Clock on the outside, but it’s a Life Lab once you’re in.”

The app does offer some solid advice. Get more steps in. Try to stick to a sleep schedule. Limit alcohol. Eat five servings of fruits and vegetables. Do this consistently for the most benefit. There’s some personalized advice. Mine is centered on getting my liver back to normal. But if the “life lab” is mainly telling me to do more of what I’m doing, to focus on lifestyle interventions — if that’s all any of these health apps do, did they really need my blood?

If there’s one thing Franson and I agree on, it’s that we’ll all die someday. Everyone and everything you love will die also. That’s objectively scary and painful.

“If we were all a lot healthier, didn’t eat processed food, exercised more, focused on sleep, did less drinking and smoking — the average life expectancy would be higher than it is. There’s no debate about that,” says Franson. “We’re more informed than ever; even so, we’re not smarter than we ever were. We just have much more information … but we don’t have a great solution to the uncomfortable fact that we’re all going to die.”

I recognized perhaps a bit of my father in what Franson had to say. He liked control and certainty, and insofar as my father could influence death — the ultimate uncertainty — he did. He took daily walks and did light calisthenics well into his 70s. He obsessed over his diet, took endless supplements, and went to the doctor often. He always boasted that he’d live to 100 years old. He didn’t. Though most people would say dying at 88 is a good run, he spent the last 10 years of his life battling Parkinson’s, eventually losing control of his limbs and forfeiting his memories to dementia. More diseases that can’t be found in your blood. Even so, he refused to cede that his end was out of his hands. It led to a lonely, painful, and drawn-out death.

Perhaps where we differ is that I’m less afraid of dying. I’m more worried about prolonged sickness, of holding on just to hold on. Counterintuitively, I’m hoping my blood panels don’t extend my Death Clock estimate further into the future. It’s not that I don’t want to live a long life. I’m just uninterested in a long life without good health. I went into this experiment skeptical, but open to the possibility I could learn something.

So far, I’ve mostly decided my blood never held the answer to my real question. How do I live a life that allows me to die well?