Episode 386: What Labs Should I Ask My Doctor For? Basic Blood Work (& Beyond)
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Most people walk out of their routine doctor’s appointments with “normal” labs and zero clarity about why they’re tired, inflamed, or not feeling like themselves. In this episode, Erin breaks down what your CMP, CBC, and lipid panel actually measure, and why routine bloodwork often misses the early signs of metabolic dysfunction, inflammation, thyroid issues, and nutrient depletion.
So what are the best add-on markers to ask for that will give you a genuinely comprehensive picture of your health? From fasting insulin and hemoglobin A1c, to thyroid antibodies, ANA, HS-CRP, ferritin, vitamin D, and GGT, Erin provides critical context about each of these – and how each one uncovers clues your doctor’s standard panel never will.
P.S. Download our FREE bloodwork checklist for the exact labs Erin recommends in this episode.
In this episode:
Why “normal” blood work doesn’t always mean “optimal,” and how functional ranges reveal imbalances years before disease
The must-have trio for evaluating metabolic health beyond fasting glucose: insulin, hemoglobin A1c, and uric acid
The #1 liver marker missing from most CMPs and how it reflects toxin load, oxidative stress, and glutathione depletion
Why TSH alone is an incomplete thyroid screen, and how thyroid antibodies can detect Hashimoto’s years earlier
How markers like ANA, ferritin, HS-CRP, and RBC magnesium work together to uncover hidden inflammation and autoimmune activity
Resources mentioned:
FREE GUIDE: The 19 Blood Tests You Should Ask For
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Episode 212: A Functional Medicine Approach to Labs
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Traditional lab testing, it's basically goes like this disease, normal disease. So if it's too low, that's a disease in the middle, you're normal, too high disease. Whereas a functional medicine lens, the spectrum is a little bit more varied. So there's out of range, there's malfunction. We're screening for imbalances. We're looking for more tighter ranges, reference ranges, more optimal ranges because we're really trying to screen for that optimal, optimal health. So it's important to understand that traditional reference ranges for conventional blood work don't always represent optimal health.
Erin Holt:
Welcome to The Funk’tional Nutrition Podcast, spelled with a K, because we do things a little differently around here. I'm your host, Erin Holt, and I've got 15 years of clinical experience as a functional nutritionist and mindset coach, creating a new model that I call Intuitive Functional Medicine™, where we combine root cause medicine with the innate intelligence of your body. This is where science meets self trust. Your body already knows how to heal, and this show is going to show you how. If you're looking for new ways of thinking about your health, be sure to follow and share with a friend, because you never know whose life you might change.
What labs should you ask your doctor for? We're going to talk about basic blood work and a little bit beyond. In today's episode, I'm going to try to make this one quick and dirty. I have a team meeting in exactly 40 minutes, so let's see if I can pull this one off. My mom gotta shout out share.
Erin Holt:
Bear recently asked me this question. She's like, I'm going to my doctor just for annual, like typical standard issue lab work, routine blood work, what should I make sure he tests for? And I thought this was such a great question and such a great episode to bring to the show. Today we're going to pull it back to the basics. I'm going to use plain speak as much as possible here. So this is not going to be a practitioner level episode. This one one's just really for the average person who doesn't want to feel like they need a health degree in order to understand what labs to ask your doctor for. Okay, so what does routine lab work typically look like? Most conventional annual checkups include two main panels, the CMP or comprehensive metabolic panel, and then the cbc, which is a complete blood count. And then along with those, we can sometimes see docs add on a lipid panel, TSH or other thyroid markers, hemoglobin A1c and vitamin D.
Erin Holt
Those are some of the more common ones we will see. And I would still consider those basic or routine lab work, but just understand that those are not part of a cmp, so they wouldn't automatically be run. If you're going to your doctors and say, hey, can I have a comprehensive metabolic panel? They're not going to just like pop on a TSH or pop on a lipid panel. Those are different labs. So what was on my mom's order as her comprehensive routine annual checkup was a cmp, a cbc, a standard lipid panel, and a tsh. And when she said, is this enough? When she sent this to me, she's like, is this enough? I'm like, it's not. Here's what else I want you to ask him for. So we're going to get into all of that today.
Erin Holt
But when you're looking at all of this, when you're looking at this lab order and then the results, it can seem like a lot of lab work. So sometimes our clients will come to us and they'll tell us, I've had all my labs tested, I've had all the lab work done, but this is really more so a starter package to rule out some of the big stuff. And it's all good. These are really important labs. But it really is kind of like the baseline. And we have to remember what your doctor is looking for in screening for is going to be different than what we're looking for from a more functional root cause preventative lens. Your doctor is always going to be screening for disease and we're looking for more patterns of imbalance before disease. That way we have the opportunity to intervene before it gets to a disease state.
Erin Holt
Now, these are kind of broad strokes, generalizations, but I get a lot more into this in episode 212 of the podcast, A Functional Medicine Approach to Labs. And I talk about the differences between functional medicine and conventional medicine in terms of how we approach lab testing and how you can utilize very basic lab work through a more functional lens. But traditional lab testing, it's basically goes like this disease, normal disease. So if it's too low, that's a disease in the middle, you're normal, too high disease. Whereas a functional medicine lens, the spectrum is a little bit more varied. So there's out of range, there's malfunction, we're screening for imbalances, we're looking for more tighter ranges, reference ranges, more optimal ranges, because we're really trying to screen for that optimal health. So it's important to understand that traditional reference ranges for conventional blood Work don't always represent optimal health. Sometimes we're using the standard reference ranges and sometimes we're using different reference ranges, again screening for optimal health versus just ruling out disease.
Erin Holt
So we're looking for patterns and we're using the context of your symptoms and other lab markers to really help us assess what's going on here. So obviously that's a really big discussion and we won't be getting into the specific lab reference ranges that we screen for and what to do if things are high and low and all of that. That's not what today's show is about. Today is really about what's going to be on your routine blood work, what's going to be on that cmp, what's going to be on that cbc, what it shows, what it might not tell you, and then other basic labs that you can ask your doc for to get an even more comprehensive look at your health. So let's dive in. We're going to start with the CMP Comprehensive Metabolic Panel. This is typically looking at first 14 markers, and it's a blood test that's used to evaluate blood sugar, electrolyte status, liver function, kidney function, and then acid base balance. So all really important stuff in the body.
Erin Holt
So we're looking at glucose, which is the sugar in your blood. We're looking at electrolytes, calcium, sodium, potassium, chloride, CO2. These tell us about hydration levels, acid base balance. We're also looking at kidney function with BUN and creatinine. Albumin is one that will be on a cmp. That's a protein found in the blood and that can indicate problems if it's out of balance. A CMP is also looking at liver enzymes, so alt, ast, when those are elevated, that can indicate liver inflammation or toxicity, toxin exposure. So all of that is really good information, super valid, super important, but it's not a lot of information.
Erin Holt
Our practitioner Rachel here says it's very scarce in skimpy, which I completely agree with. So remember, your doctor is disease screening. So this can really help us rule out some things and can also pick up on some big scary stuff. It can flag major organ damage, overt diabetes or dehydration. The CMP is kind of like a are you still alive test, not so much a are you thriving test. So good information, but not a ton of information. Then we have the cbc, which is a complete blood count. And the CBC looks at your red and white blood cells, it looks at your platelets.
Erin Holt
It's essentially screening for how do you transport oxygen, fight off Infection, how do you clot blood? Again, all super important stuff. So we're looking at your WBC or white blood cell count. That can tell us about your immune system. It can tell us about infections that you might be fighting off. We're looking at RBC or red blood cell count, hemoglobin, hematocrit. That tells us about oxygen capacity. It can tell us about anemia risk. We're looking at red cell size, red cell color, which can hint at nutrient deficiencies like iron, B12, folate, and then platelets as well.
Erin Holt
So how you clot and repair tissue. So cbc, super important, catches a lot of problems. See, CBC is also giving us a general overview of what's happening with the immune system. So your WBC or your total white blood cell count is really looking at all the cells, all the innate cells, all the adaptive cells of your immune system. Neutrophils, lymphocytes, monocytes, sonophils, basophils. When the white blood cell count is high, that's really indicating an active infection. But when it's low, this is when we can start to suspect autoimmunity because the immune system is essentially suppressed, exhausted, compromised. And so a CBC can really give us a baseline and show us what your normal is.
Erin Holt
And you can use this to follow up routinely to kind of check in on the health of your immune system, which is kind of an important thing to do with autoimmunity. So that's not always used that way, but it certainly could and should be used that way because it's a pretty inexpensive test that can give us a lot of data.
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Erin Holt
So that's your CMP, that's your CBC. Now let's talk about your standard lipid panel which is run pretty routinely on this. Usually there's four main markers, sometimes a little bit more, but the four main are total cholesterol.
Erin Holt
So this is the total amount of cholesterol in your blood. That includes both HDL and ldl. We're looking at LDL cholesterol, low density lipoprotein, and this is what we consider the bad cholesterol. Lipoproteins are the transporters of cholesterol. So LDL essentially take cholesterol from the liver and into the tissue. And then we have HDL cholesterol, which is the quote, unquote good cholesterol. And that is pulling cholesterol from the tissues and bringing it back to the liver. And then the fourth marker are triglycerides, a really important marker because high levels really do increase heart disease risk.
Erin Holt
And triglycerides are a very good early marker for metabolic dysfunction. So we should be keeping our eyes on triglycerides. Now, here's why context matters. Because this is telling us what's happening, but it's not telling us why. And there are different reasons or different causes for these markers on a lipid panel to being off. There's different reasons for dyslipidemia. One is genetics, but two is lifestyle factors. So this is sleep, diet, movement, stress.
Erin Holt
Three is inflammation, again, diet, infections, toxin exposure, gut inflammation, intestinal permeability or leaky gut inflammation anywhere in the body can impact what's happening with cholesterol. Metabolic dysfunction can really influence these numbers as well. So things that are happening with your blood sugar, with insulin signaling and then finally hormones can really impact this too. Estrogen, testosterone, adrenal hormones can play a role here. An under functioning thyroid is a huge impact on cholesterol. So hypothyroidism can lead to high total and LDL cholesterol. So point is, just seeing these four markers tells us, hey, yeah, there's some things going on, but it doesn't tell us the root drivers of why these things are going on. And that's really why we like to take a more comprehensive look.
Erin Holt
We like to add on more markers so we can start to understand, okay, what is driving this dysfunction. If we're seeing evidence of dysfunction in the body, what is driving this dysfunction? Because it's really hard to change things that we don't understand. We need to know where the right place to intervene is. So when we're working with clients in our practice, we are running routine lab work on just about everybody. And this is what we're looking for. This is what our custom blood work panel is, what we consider to be a comprehensive panel. And the reason that it's more comprehensive is because it's going to provide more context. Is it going to provide all the context, nope.
Erin Holt
There still might be more information that we need, but it's a really good start. So we start with the cmp, the CBC and the standard lipid panel. All the things that I just talked about. Like I said, super important, super valid. We need those. That is like the starter pack. Really good, basic foundational information. But from there we add on more markers.
Erin Holt
So I want to explain what those markers are and why we're looking at them. Hemoglobin A1C, it's written out. HbA1C is a really great marker for blood sugar. So the CMP does include glucose and I always recommend doing that one fasted. We want to see fasting glucose. But fasting glucose is a moment in time. It's what's happening with your blood sugar at the time of the blood draw. Whereas HbA1c or hemoglobin A1c reflects your, your average blood glucose levels over the past two to three months.
Erin Holt
So it's just a more comprehensive look because it's a longer term picture. And then in addition to that, we're also looking at insulin. Again, we like to see this fasting, so we're adding insulin to it as well because this can help us detect insulin resistance early, before it even leads to significant glucose changes. So fasting glucose, fasting insulin. Hemoglobin A1C provides a much more robust picture of metabolic health, blood sugar signaling. And then we can also add on uric acid, which is another early marker of metabolic stress. It can correlate with blood sugar and fructose metabolism and inflammation. Now, speaking of inflammation, we're also always adding on HS CRP or high sensitivity C reactive protein.
Erin Holt
This marker is used conventionally as a risk marker of risk for cardiovascular event. It's a predictive marker of cardiovascular disease, but it's also a marker of acute inflammation. So it's measurable inflammation at the time of the blood draw. So if this is elevated, it is our job to go inflammation hunting because it is telling us that inflammation is high, but it's not again, telling us where the driver of inflammation is. So if you've listened to the podcast before, we talk a lot about going inflammation hunting. That is kind of part of our job as functional practitioners. And so if we see this, we're like, okay, inflammation is here. Now it's our job to figure out what's driving that inflammation.
Erin Holt
Next up we have homocysteine. This reflects methylation, folate, vitamin B6, vitamin B12 deficiencies. High levels of homocysteine can contribute to inflammation and affect blood vessels and cardiovascular risk. So that's an important one to add on. Another one we're looking at is ggt, which is another liver enzyme that is not usually included in the cmp. So this is an enzyme that's present in liver cells, but also kidney, prostate, pancreas, biliary tract cells as well. And it is used to rule out liver in bile duct conditions. But it's also a sensitive marker of oxidative stress, of toxin load, xenobiotic exposure.
Erin Holt
And GGT has an inverse correlation with glutathione. I've talked a lot about glutathione as our body's main antioxidant. So it's extremely important for liver health, for detoxification, to prevent oxidative stress. It's also really important for autoimmunity. Glutathione is a big deal in the body and so we can use GGT as a marker for glutathione depletion. So we really like to see that one as well. And then we're also doing a full thyroid panel. Yes, this is part of our comprehensive panel because thyroid issues are so commonplace, especially, especially especially in women and we love to screen for this so we can catch things early and then we have this opportunity to intervene before it becomes a big huge problem.
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Erin Holt
So a full thyroid panel to us is TSH, thyroid stimulating hormones.
It's free and total T3. So those are two different markers. Free T3, total T3. We're also looking at T4, free T4, total T4, we're looking at reverse T3, we're looking at T3 uptake and then we're looking at two antibodies, TPO antibodies and thyroglobulin antibodies. That's often written out as TgAb on a lab. Now if you remember from the start of the show, I said that they had popped a TSH onto my mom's labs because for her they were thinking Hashimoto's. They wanted to screen for Hashimoto's. So that was the the rationale as to why they added TSH to her labs.
Erin Holt
And I had to explain to her why that was not a good way to screen for Hashis. And we really needed to see those antibodies if we wanted to look at Hashimoto's. So Hashimoto's thyroiditis is the most common cause of hypothyroidism. It's characterized by the elevated presence of those antibodies, antithyroid peroxidase anti TPO antibodies and then antithyroglobulin anti TG antibodies. So these antithyroid antibodies with T cell activation is what leads to the destruction of the thyroid gland. But it's important to understand that Hashimoto's doesn't start in the thyroid. It starts in the immune system. It is an immune system problem with an endocrine fallout.
Erin Holt
So this is why using TSH to screen for Hashimoto's is not really a great practice. Because by the time TSH changes, your thyroid cells have already been damaged. Antibodies often elevate years before TSH does. So we don't want to wait until there's already destruction of the gland before we intervene. If you wait until TSH goes high before you make any intervention, waiting way too long. So you're not catching the beginning of the disease process. You are catching the fallout. You're catching the aftermath.
Erin Holt
You're catching it while the disease process has already been underway, potentially for years. Can you tell I'm passionate about this? Screen for those thyroid antibodies. It's so, so, so important. I say this as somebody who has been working in women's health for a long time. Screen for those antibodies. It's important. And now speaking of autoimmunity, another marker we're always adding to lab tests, for the most part, depending on the symptoms of the person, is a N, A and A stands for antinuclear antibodies. And this is a marker for autoimmune activity in the body.
Erin Holt
And people can test positive for ANA years before they actually get diagnosed with autoimmunity. So this means if this A N A is elevated, this means somebody in a susceptible state. And now's the time to get busy. Let's get down to business. We can address the triggers of inflammation, we can address any immune system disruption and hopefully redirect the ship and get it back to homeostasis, get it back to balance rather than just let the autoimmune process continue unchecked. So A and A is a great one to ask for, especially if you have like random aches and pains, random symptoms, chronic symptoms that just can't be explained, can't go away. ANA is not going to tell you what type of autoimmune condition you have. It's just going to tell you that, hey, there is autoimmune activity happening in the body.
Erin Holt
So that generally requires some follow up after a positive A and A. And then let's switch gears into nutrients. We are looking at some nutrients through blood work. Vitamin D being a very big one. Vitamin D25, just your basic basic vitamin D That's an important one to add on there. We know how important it is from tip to tail for like our overall health. So be screening for vitamin D iron panel. So that includes iron, serum iron, iron binding capacity, percent saturation, so that gives us a full iron picture.
Erin Holt
Plus we're looking at ferritin, which is iron storage. But ferritin is also an inflammation marker, so it's called an acute phase reaction, meaning that during inflammation, during infection, ferritin synthesis is stimulated so ferritin can go up. So if you see high levels of ferritin, we can assume that you're getting an inflammatory oxidative response. And if we see low ferritin, we can assume that your iron stores are depleted and both sides of that spectrum are problematic and need to be addressed. And the last one is RBC magnesium or red blood cell magnesium. Magnesium is such an important mineral and it's just an important one to screen. It's a pretty inexpensive test that you can add to lab work. And then of course we're doing more testing as needed.
Erin Holt
But this is a really good basic, while also being comprehensive blood work panel that we start many of our one to one clients with. These are all basic labs that your doctor can order. And so if you're looking for more than just a CMP or a cbc, definitely ask your doc about adding some of these onto your blood work. And, and if some of them come back kind of wonky and you're not really sure what your next steps are, that's what we're here for. So reach out to us. We work with clients one on one and we help rebuild your health from the inside out. And if we need more in depth testing, like if your inflammatory markers are high, for example, and we're not really quite sure why we get to go inflammation hunting. So we have gut testing that we can do, we have hormone testing that we can do, we have a lot of different tests at our disposal and we can help you get to the bottom of what's going on with you.
Erin Holt
So we will link up application work with us one on one in the show notes, we will also link up, we'll map all of this out, my team and I, and put this in a nice PDF guide because I know I just threw a lot of lab markers at you, but I bet it would be really helpful for you to have it in one sheet of paper in one place. So we will do that for you. We'll link that up in the show notes and you can also hit us up on Instagram if you want to grab that PDF guide, but hopefully this was helpful. Definitely send this to somebody who it could help help. I love you guys and I will check you next week.
Thanks for joining me for this episode of the Funk’tional Nutrition Podcast. Please keep it mind this podcast is created for educational purposes only and should never be used as a replacement for medical diagnosis or treatment. If you got something from today's show, don't forget, subscribe, leave a review, share with a friend, and keep coming back for more. Take care of you.