The first step in taking control of your health
I spend a lot of time in this newsletter talking about taking charge of your own health.
Our health isn’t something that just happens to us. It’s the product of a million decisions that we make based on the information that we have available to us and how we interpret that information. That goes for medical decision making the same way that it goes for our lifestyle.
As Matt Yglesias has said, we’re all doing our own research. The reason that I try to provide digested medical information is because it helps you make your own decisions. Due to the way that medicine and science are covered in the media, even informed people may not have the necessary context to interpret medical news in a useful way.
With a lot of the topics that I write about, I get questions from individual readers asking how the topic that I’m covering applies to you.
After all, most of us aren’t interested in abstract news about heart disease prevention - we want to know if we’re going to have a heart attack and how we can prevent ourselves from having one. We don’t care as much if the advice doesn’t apply to ourselves.
So when I get a question about whether you should take this medication or whether you should have that test done, my real answer is usually going to be the same:
I have absolutely no clue whether it’s right for you.
As you may have noticed from the way that I write about things, I am a firm believer that each person is different and almost every medical case is different. The vast majority of medical interventions are not one size fits all.
Without knowing your medical history, your family history, being able to examine you, and what all of your medical testing shows, it’s impossible to provide individualized information that’s actually useful.
You can’t know what’s going on with your own health if you never get bloodwork checked.
Your bloodwork is the window into your own health. Without getting bloodwork done, you’re essentially flying blind.
But there’s a lot of disagreement about what we should be checking and when should be checking it.
There was a controversy a few years ago after Mark Cuban suggested that everyone should get regular bloodwork done to understand their own health status. The pushback to Cuban was hard and swift, probably best exemplified by Aaron Carroll’s characteristically thoughtful and super smart response where he emphasizes a number of the problems created with regular bloodwork:
This is why I teach residents and medical students never, ever to order blood tests unless they are looking for a specific problem. Do you think that the patient is anemic? Then it makes sense to check a hematocrit value (the number of red blood cells). Are you worried they might have diabetes? Then you should check a glucose value. But getting those tests in a vacuum isn’t helpful at all…
When a lab test picks up something that isn’t real, it’s called a false positive. It’s a lab value that is “abnormal” but there really isn’t a health issue. When someone is healthy, an abnormal value is much more likely to be a false positive than a true positive. This is especially true when a test has a low “specificity“…
Most people, even physicians, have a hard time ignoring “abnormal” lab values. They want to work them up. This leads to excess testing, potential harm, and a lot of money wasted. False positives are just that – false. You wind up on a “diagnostic Odyssey” where you chase abnormal value after abnormal value, and never get to the end.
And so while he’s totally right about the risks here, especially when applied across a population indiscriminately, I disagree with his conclusion that checking regular bloodwork has no place in a general health assessment.
As a cardiologist, I take care of people with chronic disease that goes on silently for years before it manifests with overt symptoms. And because many of the symptoms of cardiovascular disease happen insidiously, my patients frequently interpret symptoms of disease as “just getting older and slowing down” for a long time before they come to medical attention.
For the purposes of understanding what’s going on with your own health, getting your bloodwork done and working with an expert to interpret this information in context is the best way that you can take charge of your own health.
Of course there’s truth to the concern about overtesting, false positives, and diagnostic Odysseys, but if you’re engaged in your own health, looking at your bloodwork regularly gives a level of insight that nothing else can.
The key is to be able to interpret that information in the right clinical context and not overreact what you see. That means the bloodwork needs to be interpreted in the context of who the patient is and how they are feeling.
The advice to get bloodwork done is even more important if you’re having symptoms of anything
Let’s say you’re short of breath when you walk up the stairs. I can’t tell you that you’re out of shape until I’ve ruled out that you’re anemic. And I can’t do that by asking you questions.
Let’s say you’re feeling depressed and are sleeping all the time. I have no idea whether we should think about treating depression until I’ve ensured that your thyroid is functioning normally.
Let’s say your muscle mass is decreasing and you have no libido. I have no idea whether you need to workout more or whether it’s because your testosterone is low.
It’s only after we’ve made a diagnosis that we can even begin to consider what the treatment should be.
Some common tests that doctors check and what they tell us
Most of the time, you don’t get every blood test under the sun. The common ones below are things that doctors check essentially every visit that you have. Depending on the level of interest and curiosity from readers in reaction to this post, it may be worth going into these in more detail in a future newsletter.
Complete blood count (CBC) - measure of your red blood cells, white blood cells, and platelets (a type of blood cell involved in blood clotting). We get detailed information about the number and type of each of these cells, helping to diagnose anemia, bleeding disorders, and infections.
Basic metabolic panel (BMP) - measure of various electrolytes (sodium, potassium, chloride), a window in your pH (measuring your bicarbonate levels), estimation of kidney function (your BUN and creatinine), and your blood sugar levels. Often the first sign of chronic and progressive kidney disease is abnormal creatinine on standard bloodwork.
Liver function tests (LFTs) - this is a bit of a misnomer, because these tests don’t actually tell you much about liver function. But we get a window into some liver enzymes (AST and ALT) which tell us about metabolic health and some other things. Abnormal AST and ALT can signify fatty liver, hepatitis, or chronic liver disease. We also look at your bilirubin levels and your levels of total protein and albumin. Low albumin can signify malnutrition or chronic disease.
Sometimes a BMP and LFTs are combined into something called a comprehensive metabolic panel (CMP).
Lipid testing - look at your total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglyceride levels. There’s a ton of nuance to how we interpret this that’s worth a deep dive at another time.
Hemoglobin A1c - a marker of your average blood sugar over the past 2-3 months. Tells us about diabetes and prediabetes.
In a patient who is experiencing abnormal symptoms, the list of blood tests expands based on what you’re describing
When I have a patient report that something isn’t working right, bloodwork is almost always the first step.
There are blood tests looking at every organ system that can be used to diagnose essentially any symptom that you can think of.
This is where individualizing care comes in - and also why it’s so important to mention things that aren’t working right to your doctor. If we don’t know it’s an issue, we can’t read your mind and we won’t test you for it.
I have my own set of specialized cardiovascular prevention tests that I sent for patients who want detailed insight into their own personal risk of cardiovascular disease.
The bottom line here: the information we get from your bloodwork is really important but needs to be interpreted in the right context
I am a complete believer in the power of understanding your own health and taking active steps to improve it.
And while the way that you feel on a daily basis, the quality of your sleep, your energy levels, and your physical abilities all play a role in a health assessment, your bloodwork plays a really important role as well.
Blood tests are a vital part of understanding your health.
Getting these tests is not without risk, as I discussed above, but I’ve been persuaded that the benefits are much greater as long as the information can be viewed through a personalized clinical context.
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