The entire foundation of modern healthcare—the lab ranges, the guidelines, the "normal" values—is built on a LIE. Why "Normal" Lab Results Don't Mean You're Healthy

The Uncomfortable Truth About Laboratory Reference Ranges

You've probably experienced this: You feel exhausted, foggy, off. You go to your doctor, run labs, and hear those familiar words—

"Everything looks normal."

But you don't feel normal. You feel terrible.

Here's what your doctor probably doesn't know: The "normal" ranges they're comparing you to aren't based on optimally healthy people. They're based largely on sick populations.

And it gets worse.

Where Do "Normal" Ranges Actually Come From?

Most laboratories use what's called the "indirect method" to establish reference ranges. This means they pull data from their existing laboratory information systems—results from patients whose doctors ordered tests.

Think about that for a moment.

When does a doctor order a lab test? When they suspect something is wrong.

The International Federation of Clinical Chemistry (IFCC)—the global body that sets laboratory standards—published this in Clinical Chemistry and Laboratory Medicine:

"The use of laboratory data raises concerns as most requests will be on individuals suspected to be in a 'disease state' meaning data could be biased."

In other words: The "normal" range is calculated from people who were sick enough to need testing in the first place.

Sicker Patients Dominate the Data

A 2014 study in BMC Medical Informatics and Decision Making proved something remarkable: The sicker a patient is, the more lab data they contribute to reference ranges.

Researchers found that the sickest patients (ASA Class 4) had five times more days with laboratory results than healthy patients. This means their values are over-represented in the databases used to calculate "normal."

"The selection of records with sufficient data... may bias the sample towards patients who are sicker than the population from which the sample is drawn."

When your labs come back "normal," you're being compared to a dataset skewed toward illness.

"Normal" Means "Not Dying"—Not "Thriving"

Here's where it gets really interesting.

The American Board of Family Medicine published a paper in 2025 that stated this explicitly:

"The recommended daily allowance (RDA) and by corollary, the normal values, are geared to provide a value that prevents disease in 98% of otherwise healthy individuals. RDA is not designed for optimum health."

Let that sink in.

Your "normal" vitamin D level? It's the level that prevents rickets—a disease from the 1800s. The cutoff is 20 ng/mL.

But populations with natural sun exposure have levels of 50-80 ng/mL. That's 2-4x higher than "normal."

Your "normal" folate level? It's >4 ng/mL—the level that prevents megaloblastic anemia. But research shows optimal folate for cardiovascular and neurological protection is >13 ng/mL.

"Normal" keeps you out of the emergency room. It doesn't make you feel amazing.

The Thyroid Example

Consider TSH (thyroid-stimulating hormone). The standard reference range is roughly 0.4-4.5 mIU/L.

But research published in Clinical Chemistry found that up to 30% of people with TSH above 3.0 mU/L have undiagnosed autoimmune thyroid disease.

The National Academy of Clinical Biochemistry has suggested the "true normal" TSH range should be 0.4-2.5 mIU/L—nearly half the width of standard ranges.

How many people are walking around with a TSH of 3.8, being told they're "normal," while experiencing fatigue, weight gain, and brain fog?

The reference range includes them because enough people with subclinical thyroid disease got tested that their values became "normal."

The Testosterone Collapse

Here's perhaps the most alarming example.

Published research shows that testosterone levels in young men have dropped dramatically:

• 1999-2000: Average testosterone in men 15-39 was 605 ng/dL

• 2015-2016: Average dropped to 424-451 ng/dL

That's a 25-30% decline in just 16 years.

What happened to reference ranges? They were adjusted downward to match the declining population.

A 30-year-old man today with a testosterone of 400 ng/dL is told he's "normal." His grandfather at the same age likely had 550+ ng/dL—and that was considered normal then.

The bar keeps dropping because the population keeps declining. You're being compared to a shrinking standard.

The Math That Should Concern You

Here's a statistical fact most doctors don't mention:

Reference ranges are defined as the central 95% of tested values. By definition, 5% of perfectly healthy people will have "abnormal" results.

But here's the flip side the American Board of Family Medicine calculated:

"If 20 tests are done on a normal/healthy person... 64.2% of 'normal' patients will have at least one 'abnormal' test result."

The system is designed to label healthy people as abnormal and to miss sick people who fall within the "normal" range.

What This Means for You

When your doctor says "your labs are normal," what they're really saying is:

"Your results fall within the range of other people who were tested—many of whom were sick, some of whom had undiagnosed disease, and all of whom were measured against standards designed to prevent disease rather than optimize health."

That's a very different statement than "you're healthy."

The Alternative: Optimal Ranges

This is why a growing movement of practitioners uses optimal reference ranges instead of standard ranges.

Optimal ranges ask a different question: Where should this value be for you to feel your best and have the lowest risk of disease?

For vitamin D, that might be 50-70 ng/mL instead of "above 20."

For TSH, that might be 1.0-2.0 mIU/L instead of "under 4.5."

For testosterone, that might be based on what healthy men should have—not what the average declining man has today.

The Bottom Line

"Normal" is a statistical construct, not a health assessment.

The reference ranges on your lab report were:

• Derived largely from sick populations

• Designed to prevent disease, not optimize function

• Adjusted over time as population health declines

• Statistical averages that tell you nothing about YOUR optimal levels

If you've ever felt dismissed with "your labs are normal" while knowing something was wrong—you weren't crazy.

The system just wasn't designed to detect whether you're thriving. It was designed to detect whether you're dying.

There's a massive gap between those two states.

And you deserve better than "not dying."

References:

1. Jones GRD, et al. "Indirect methods for reference interval determination." Clin Chem Lab Med. 2018;57(1):20-29.

2. "Hidden in plain sight: bias towards sick patients when sampling patients with sufficient electronic health record data." BMC Med Inform Decis Mak. 2014;14:51.

3. Sikaris KA, et al. "Interpreting Normal Values and Reference Ranges for Laboratory Tests." J Am Board Fam Med. 2025.

4. "The Role and Limitations of the Reference Interval Within Clinical Chemistry." Frontiers/BJBS. 2024.

5. Lokeshwar SD, et al. "Decline in Serum Testosterone Levels Among Adolescent and Young Adult Men in the USA." Eur Urol Focus. 2021.

6. Spencer CA. "TSH Reference Limits: New Concepts and Implications." Endocr Pract. 2020.