Bloodwork: The Man Behind the Man Behind the Man

You can look healthy, feel healthy and still have something worth paying attention to under the hood. Bloodwork isn’t about becoming your own doctor. It’s about understanding the fucking dashboard.

I spend a lot of time talking about things you can see.

Bodyweight.

Muscle.

Body fat.

Waist measurements.

Progress pictures.

How much weight is on the bar.

But eventually I reached an age where I started caring considerably more about the shit I can’t see.

Blood glucose.

Cholesterol.

Kidney function.

Liver markers.

Red blood cells.

Hemoglobin.

Inflammation.

The numbers underneath the numbers.

The man behind the man behind the man.

Because you can have abs and still have shitty bloodwork.

You can also get one abnormal laboratory result, immediately assume you’re dying, spend four hours on Google and discover that apparently you have six different cancers and fourteen minutes to live.

Neither approach is particularly useful.

Take Ownership Without Playing Doctor

Here’s something I’ve learned as I’ve gotten older:

You need to participate in your own healthcare.

Your physician may be excellent.

But your doctor sees a lot of patients.

You live inside your body every fucking day.

That doesn’t mean you diagnose yourself.

It doesn’t mean you start treating yourself based on something you read on Reddit.

And it definitely doesn’t mean:

“My ALT was three points high, so I ordered $400 worth of supplements from a guy named LiverKing69.”

It means you learn enough to ask intelligent questions.

What did we test?

What does this marker actually measure?

Has it changed?

Could something I’m doing affect the result?

Should we repeat it?

Is there another test that provides additional information?

Does this number actually mean something when considered alongside everything else?

Taking ownership of your health doesn’t mean replacing your physician. It means showing up prepared to have a better conversation with them.

Start With the CBC

One of the most common blood tests is the complete blood count—or CBC.

It looks at several components of your blood, including red blood cells, white blood cells, hemoglobin, hematocrit and platelets.

It’s basic.

It’s common.

And there’s a surprising amount of information sitting on that page.

Red Blood Cells: Your Oxygen Delivery System

Red blood cells—RBCs—have one particularly important job:

Move oxygen around your body.

Inside those cells is hemoglobin, the protein that binds oxygen.

Your lungs load oxygen onto hemoglobin.

Your circulatory system transports those red cells.

Your tissues use the oxygen.

That’s pretty fucking important if you’re interested in remaining alive.

So when I look at a CBC, I’m interested in more than whether the laboratory printed NORMAL next to everything.

I’m looking at the relationship between several numbers.

RBC Count

Your RBC count is essentially how many red blood cells are present in a given volume of blood.

Too few can occur with different forms of anemia and other conditions.

Too many can occur for numerous reasons as well—including circumstances involving oxygen availability, dehydration and certain medical conditions.

One number doesn’t tell you the cause.

It tells you:

Here’s something to understand in context.

Hemoglobin

Hemoglobin—usually abbreviated Hgb—is the oxygen-carrying protein inside red blood cells.

If hemoglobin is low, your blood’s capacity to transport oxygen may be reduced.

That can matter for everything from fatigue to exercise tolerance depending on the cause and severity.

Again:

The number is the beginning of the question, not necessarily the answer.

Hematocrit

Hematocrit—Hct—is the percentage of your blood volume made up of red blood cells.

If your hematocrit is 45%, roughly 45% of that blood volume consists of red cells.

This number can also move with hydration status.

That’s important.

If you’re dehydrated, the liquid portion of your blood can decrease and hematocrit can appear higher because the blood is more concentrated.

So one slightly unusual number after you haven’t had enough water isn’t automatically a medical catastrophe.

Context.

We’re going to use that word a lot.

MCV: How Big Are the Cells?

MCV means mean corpuscular volume.

In normal-human language:

What’s the average size of your red blood cells?

That becomes useful because different patterns of anemia can produce differently sized red cells.

Low MCV can point the evaluation in one direction.

High MCV can point it somewhere else.

That’s where things like iron, B12, folate and other causes eventually enter the conversation.

And conveniently, those are exactly the kinds of things we’re covering in Part II.

White Blood Cells: Your Immune System Has Receipts

Then there are white blood cells—WBCs.

They’re part of your immune defense.

When something changes with your WBC count, there are numerous possible explanations.

Infection.

Inflammation.

Medications.

Immune conditions.

Bone marrow disorders.

Physiological stress.

And other causes.

Which means:

High WBC ≠ automatically “I have an infection.”

And low WBC doesn’t diagnose one specific condition either.

That’s why a CBC may include a differential.

That breaks white cells into different categories such as:

Neutrophils.

Lymphocytes.

Monocytes.

Eosinophils.

Basophils.

Different patterns can help your clinician figure out where to look next.

Notice the language:

Help figure out where to look.

Not:

One number diagnoses everything.

Platelets: Don’t Forget the Little Bastards

Platelets help your blood clot.

Too few or too many can matter for completely different reasons.

Again, we’re not going to turn this article into hematology school.

The takeaway from the CBC is much simpler:

Your blood isn’t represented by one magic number.

Look at the pattern.

Blood Glucose: One Photograph

Next up:

Glucose.

A fasting glucose measurement tells you how much glucose is circulating in your blood at that particular time.

That’s useful.

But it’s still essentially a photograph.

Your glucose changes throughout the day.

You eat.

You train.

You sleep.

You fast.

Your hormones change.

Your glucose responds.

That’s why I also care about HbA1c.

HbA1c: The Longer View

Hemoglobin A1c measures the percentage of hemoglobin that has glucose attached to it.

Because red blood cells live for roughly a few months, A1c gives us an approximation of average blood glucose exposure over approximately the previous 2–3 months.

Current CDC diagnostic ranges are:

Normal: below 5.7%

Prediabetes: 5.7–6.4%

Diabetes: 6.5% or higher.

But even A1c has limitations.

Conditions affecting red-cell lifespan or hemoglobin can distort the result.

Which brings us right back to our recurring lesson:

Understand what the test measures before deciding what the number means.

Lipids: Now We’re Talking About the Heart

This is an area I pay considerable attention to as I get older.

A standard lipid panel generally gives you things such as:

Total cholesterol.

LDL cholesterol.

HDL cholesterol.

Triglycerides.

You’ve probably heard LDL called “bad cholesterol” and HDL called “good cholesterol.”

That’s convenient shorthand.

Reality is more complicated.

LDL-C

LDL particles transport cholesterol through the bloodstream.

Elevated exposure to atherogenic lipoproteins plays a causal role in atherosclerotic cardiovascular disease.

So LDL-C absolutely matters.

But LDL-C isn’t the only thing worth understanding.

The 2026 ACC/AHA dyslipidemia guideline specifically broadened cardiovascular risk assessment beyond LDL-C alone and incorporated additional markers such as ApoB and Lp(a) in appropriate situations.

Which brings us to one of my favorites.

ApoB: How Many Damn Particles Are We Dealing With?

Apolipoprotein B—ApoB—is found one per atherogenic lipoprotein particle.

That makes ApoB useful because it provides information about the number of atherogenic particles circulating in your blood.

Think about it this way.

LDL-C helps tell you how much cholesterol is being carried within LDL particles.

ApoB helps provide information about how many atherogenic particles are carrying lipid around.

Those questions are related.

They aren’t identical.

The latest ACC/AHA guidance says ApoB can be particularly useful for refining risk in certain people, including those with diabetes, elevated triglycerides, cardiovascular-kidney-metabolic syndrome, known cardiovascular disease or low achieved LDL-C where residual risk remains a concern.

I’m not telling everyone reading this to immediately order seventeen exotic cardiovascular biomarkers.

I’m saying:

Know that LDL isn’t the entire conversation.

Triglycerides

Triglycerides are another type of fat circulating in the blood.

They’re influenced by numerous factors including diet, alcohol intake, metabolic health and genetics.

Elevated triglycerides can contribute to cardiovascular risk and, when extremely elevated, create additional medical concerns.

Again:

Don’t interpret them in isolation.

HDL: “High Is Good” Isn’t the Whole Story Either

HDL participates in cholesterol transport and historically gets labeled the good cholesterol.

But having a high HDL doesn’t automatically erase other cardiovascular risks.

The current ACC/AHA guidance specifically warns against treating apparently favorable LDL-C or HDL-C numbers as a free pass when other risk factors are present.

Your cardiovascular system doesn’t give out immunity cards.

One Test I’d Consider Discussing: Lp(a)

Lipoprotein(a)—Lp(a)—is especially interesting because its level is largely genetically determined and tends to remain relatively stable.

The 2026 ACC/AHA guideline now recommends measuring Lp(a) at least once in adulthood as part of cardiovascular risk assessment.

That’s exactly the type of thing I mean when I say healthcare evolves.

If the last time you thought seriously about cholesterol was 2006 and your entire understanding is:

HDL good. LDL bad.

There’s considerably more information available now.

Kidneys: Creatinine Isn’t Useless — But It Isn’t God

Now we’re getting into one of my favorite examples of why context matters.

Creatinine.

Creatinine is a waste product related to normal muscle metabolism, and the kidneys filter it from the blood.

Because of that, serum creatinine is commonly used to estimate kidney filtration.

That’s useful.

The problem?

Creatinine isn’t produced identically by everyone.

Muscle mass matters.

Diet can matter.

Creatine supplementation can matter.

Exercise can matter.

Age and other factors matter.

So imagine comparing a sedentary 70-year-old weighing 140 pounds with a heavily muscled 230-pound guy who resistance trains and takes creatine.

Using serum creatinine without considering context can become considerably more complicated.

That doesn’t make creatinine useless.

It means you need to understand its limitations.

eGFR: An Estimate, Not a Direct Measurement

You’ve probably seen eGFR next to creatinine on your labs.

That means estimated glomerular filtration rate.

Estimated.

There’s that word again.

It’s calculated using biomarkers and demographic information rather than directly watching your kidneys filter blood.

That’s extremely useful clinically.

But estimates have limitations.

And that’s where cystatin C becomes interesting.

Cystatin C

Cystatin C is another blood marker that can be used to estimate kidney filtration and is much less dependent on muscle mass than creatinine.

Current kidney guidelines recognize situations in which creatinine may be affected by non-kidney factors—including very high muscle mass/bodybuilding and creatine supplementation—and recommend considering cystatin C or combined creatinine-cystatin-C estimates when greater accuracy is needed. KDIGO 2024 CKD Guideline⁠

So if somebody trains heavily and has a creatinine result that looks concerning?

The answer isn’t:

“Your kidneys are fucked.”

And it isn’t:

“Creatinine means nothing.”

The answer is:

“Does this result accurately represent kidney filtration in this person, and would another measurement improve the picture?”

That’s a much smarter question.

Don’t Forget Urine

Here’s another thing people miss when talking about kidney health.

Blood isn’t the entire evaluation.

**Urine albumin-to-creatinine ratio—uACR—**can detect albumin leaking into urine and provides information about kidney damage that filtration estimates alone don’t necessarily provide.

Kidney evaluation can therefore involve both:

How well are the kidneys filtering?

and

Are they leaking protein they shouldn’t be leaking?

Once again:

One number isn’t the whole fucking dashboard.

Liver Tests: AST and ALT Aren’t Actually “Liver Function”

This is another terminology problem.

People commonly call AST and ALT liver function tests.

Technically, that’s sloppy.

AST and ALT are primarily markers of cellular injury, particularly hepatocellular injury.

ALT is more liver-specific.

AST is found in other tissues—including skeletal muscle.

That’s particularly relevant to people who lift weights.

The American Association for the Study of Liver Diseases notes that AST can originate outside the liver and that the degree of AST/ALT elevation does not necessarily correspond to the extent of liver injury.

So again:

An elevated AST doesn’t automatically mean:

YOUR LIVER IS DYING.

It means:

Something needs context.

GGT: Useful, But Not the Supreme Court of Liver Health

I like looking at **GGT—gamma-glutamyl transferase—**too.

But I’m not going to tell you it’s universally a “better liver test.”

It answers different questions.

For example, when alkaline phosphatase is elevated, GGT can help determine whether that elevation is likely coming from the hepatobiliary system rather than somewhere such as bone.

That’s useful.

But proper liver evaluation can involve:

AST.

ALT.

ALP.

GGT.

Bilirubin.

Albumin.

PT/INR.

And potentially additional testing depending on the situation.

Albumin and clotting factors provide different information about actual liver synthetic function than AST and ALT do.

Which means the phrase:

“My liver enzymes are normal, therefore my liver is perfect.”

isn’t particularly sophisticated.

Neither is:

“My AST is elevated, therefore my liver is fucked.”

Your Workout Can Matter to Your Bloodwork

This is another reason I want fitness people to understand laboratory testing.

You don’t exist in a laboratory vacuum.

You train.

You eat differently.

You take supplements.

You may carry considerably more muscle than the average person.

You may have trained hard immediately before the blood draw.

You may have been dehydrated.

That context can affect certain laboratory values.

So when you’re talking to your clinician:

Tell them what you actually do.

Don’t make them solve a fucking mystery.

How Often Should You Get Bloodwork?

Here’s where I’m not going to give you the internet-guru answer.

There isn’t one universal schedule appropriate for every human being.

Someone who’s 23, healthy and has normal previous testing is not necessarily going to need the same testing schedule as somebody who’s 55 with diabetes, hypertension, kidney disease, cardiovascular risk factors or medications requiring monitoring.

Testing frequency depends on things like:

Age.

Medical history.

Family history.

Previous results.

Medications.

Symptoms.

Risk factors.

And what exactly is being monitored.

For example, current diabetes guidance uses different A1c testing intervals depending on whether someone has diabetes, prediabetes and how well controlled the condition is.

So my advice is considerably simpler:

Establish a baseline.

Know what your numbers are.

Discuss your risk factors with your clinician.

Repeat testing at an interval appropriate for your situation.

And if something changes?

Investigate the change instead of waiting three years and hoping the fucking number gets bored and leaves.

Reference Ranges Aren’t Personal Performance Targets

This deserves its own section.

A laboratory reference range generally tells you where a result falls relative to the range established by that laboratory and testing method.

It does not necessarily mean:

Inside range = optimal.

Outside range = dying.

Clinical decisions depend on context, risk and the specific marker.

Some cardiovascular targets, for example, become more aggressive as someone’s cardiovascular risk increases. The 2026 dyslipidemia guideline specifically uses different LDL-C goals based on risk.

So don’t turn your lab report into a fucking video game where every number needs to sit perfectly in the center of the green bar.

Look at Trends

This is exactly like the fitness progress article.

One measurement is useful.

Trends are considerably more useful.

If your LDL was:

92. 92.

Then 108.

Then 126.

Then 148.

I’m interested in that trajectory.

If creatinine suddenly changes considerably from your established baseline?

Interesting.

If hematocrit keeps climbing?

Interesting.

If A1c gradually moves upward?

Interesting.

The question becomes:

Why?

What changed?

Diet?

Weight?

Training?

Medication?

Hydration?

Illness?

Something medical?

The trend gives you something intelligent to discuss with your clinician.

Don’t Chase Numbers Blindly

This is the other side of taking ownership.

You can become so obsessed with biomarkers that you start trying to manipulate every number independently.

That’s not the goal either.

We’re trying to improve health, not win Laboratory Fantasy Football.

Sometimes changing one thing affects several markers.

Sometimes an abnormal marker is a clue rather than the problem itself.

Sometimes treating the number without understanding why it changed is exactly the wrong approach.

Find the reason.

Then decide what actually needs to happen.

Bloodwork Doesn’t Replace Everything Else

Perfect labs don’t mean you’re invincible.

Blood pressure matters.

Cardiorespiratory fitness matters.

Body composition can matter.

Sleep matters.

Family history matters.

Smoking matters.

Exercise matters.

Medical history matters.

Depending on risk, other tools such as coronary artery calcium scoring can sometimes add information that blood tests can’t. Current ACC/AHA guidance, for example, uses CAC selectively to refine cardiovascular risk assessment in appropriate adults when treatment decisions remain uncertain.

Bloodwork is part of the dashboard.

Not the entire vehicle.

The Numbers I Want People to Understand

If you’ve never paid attention to your laboratory results before, start here.

Know what these are:

CBC

• RBC

• Hemoglobin

• Hematocrit

• MCV

• WBC and differential

• Platelets

Metabolic health

• Fasting glucose

• HbA1c

Cardiovascular

• Total cholesterol

• LDL-C

• HDL-C

• Triglycerides

• Non-HDL-C

• ApoB when appropriate

• Lp(a), at least once in adulthood under current guidance

Kidneys

• Creatinine

• eGFR

• Cystatin C when useful

• eGFR based on cystatin C or combined creatinine/cystatin C when appropriate

• Urine albumin-to-creatinine ratio

Liver

• AST

• ALT

• ALP

• GGT when appropriate

• Bilirubin

• Albumin

• PT/INR when clinically relevant

You don’t need to become a pathologist.

You should know what the fucking abbreviations on your own bloodwork mean.

This Isn’t About Becoming Your Own Doctor

That’s the point I want to leave you with.

There are two shitty extremes.

One is:

“My doctor said everything is fine, so I’m never looking at my results.”

The other is:

“I watched three YouTube videos and now I practice nephrology.”

😂

There’s a considerably better middle ground.

Learn.

Ask questions.

Keep copies of your results.

Watch trends.

Understand your personal risk factors.

Bring relevant information to your physician.

Ask whether additional testing makes sense when something doesn’t fit the picture.

And when something is actually wrong?

Work with somebody qualified to figure out why.

You only get one body.

I plan on being considerably more involved in maintaining mine than I was when I was 23.

And bloodwork?

That’s one of the places I start.

Because the mirror tells me what I look like.

The scale tells me what I weigh.

The gym tells me what I can lift.

Bloodwork gives me a look under the hood.

⭐⭐⭐⭐☆

Five stars require a follow-up appointment.

Raw Sources:

https://www.cdc.gov/diabetes/diabetes-testing/prediabetes-a1c-test.html

https://www.cdc.gov/diabetes/diabetes-testing/index.html

https://professional.heart.org/en/science-news/2026-guideline-on-the-management-of-dyslipidemia

https://professional.heart.org/en/science-news/2026-guideline-on-the-management-of-dyslipidemia/top-things-to-know

https://www.acc.org/about-acc/press-releases/2026/03/13/18/01/accaha-issue-updated-guideline-for-managing-lipids-cholesterol

https://kdigo.org/wp-content/uploads/2017/02/KDIGO-2024-CKD-Guideline-Executive-Summary.pdf

https://www.aasld.org/liver-fellow-network/core-series/back-basics/how-approach-elevated-liver-enzymes