How to Read Your Lab Results: What Your Doctor May Not Be Telling You

‘Your labs look normal.’ For so many patients, this is one of the most frustrating sentences in medicine. You feel terrible — exhausted, gaining weight, struggling with mood — but everything ‘comes back normal.’ What is going on?

Part of the answer lies in how lab reference ranges are set, and what ‘normal’ actually means in a conventional medical context.

How Reference Ranges Are Set

Standard lab reference ranges are generated from a statistical bell curve of the general population. The ‘normal’ range typically represents the middle 95% of the population tested. The problem: if 40% of the population is pre-diabetic, insulin-resistant, and low in vitamin D, the ‘normal’ range for those markers reflects a population that is, in aggregate, metabolically unwell.

Functional medicine uses optimal ranges — narrower bands that research associates with the best health outcomes — rather than simply ‘not-yet-diseased’ ranges.

Key Markers and Their Optimal vs. Conventional Ranges

• TSH (thyroid) — conventional normal: 0.5-4.5. Functional optimal: 1.0-2.0. Many patients feel poorly with TSH above 2.5.
• Fasting glucose — conventional pre-diabetes threshold: 100. Functional concern: above 85-90, especially with other insulin resistance signs.
• Fasting insulin — often not even tested conventionally. Functional optimal: below 5 uIU/mL. Many ‘normal glucose’ patients have significantly elevated fasting insulin.
• Vitamin D (25-OH) — conventional deficiency: below 20. Functional optimal: 60-80 ng/mL for most adults.
• Ferritin — conventional low: below 12. Functional optimal for women: 50-100 ng/mL for energy and hair health.
• hsCRP (inflammation) — any value above 1.0 mg/L warrants investigation, not just above 3.0.

Tests Your Doctor Might Not Be Running

A functional medicine evaluation often includes markers that are not part of a standard annual physical:

• Fasting insulin (not just glucose) — the earliest indicator of insulin resistance
• Full thyroid panel: Free T3, Free T4, Reverse T3, TPO antibodies
• DHEA-S and testosterone (for both men and women)
• Homocysteine — a cardiovascular and methylation marker
• Comprehensive nutrient panel including zinc, magnesium, B vitamins
• Comprehensive stool analysis for gut health
• Organic acids testing for metabolic function

What to Do With Your Results

Bring any labs you have — recent or older — to your appointment at Fundamental Wellness of Nebraska. We will review them through a functional lens, identify patterns that may have been dismissed, and determine what additional testing would be valuable.

You deserve a provider who takes your symptoms seriously and digs into the data to find real answers.