How to Read Your Blood Work: A Patient Guide

Why You Should Understand Your Labs

Most patients get blood work done, glance at the "normal" or "abnormal" flags, and never think about it again. But conventional reference ranges are based on statistical averages of the general population — including unhealthy people. A result can be "normal" by lab standards while being far from optimal. Understanding your labs puts you in control of your health decisions.

Conventional vs Optimal Ranges

Functional medicine practitioners use tighter "optimal" ranges that represent where markers should be for peak health and disease prevention, not just absence of diagnosable disease.

• ✓TSH: Conventional 0.5-4.5 → Optimal 0.5-2.0 mIU/L
• ✓Vitamin D: Conventional 30-100 → Optimal 50-80 ng/mL
• ✓Fasting insulin: Conventional 2.6-24.9 → Optimal 2-6 uIU/mL
• ✓Ferritin: Conventional 12-150 (women) → Optimal 50-100 ng/mL
• ✓hs-CRP: Conventional <3.0 → Optimal <1.0 mg/L
• ✓Homocysteine: Conventional 0-15 → Optimal <8 umol/L

The Metabolic Panel: Blood Sugar & Insulin

Most doctors only check fasting glucose and HbA1c. But by the time these are abnormal, insulin resistance has been developing for years. Fasting insulin is the early warning signal — if your fasting insulin is above 6-8 uIU/mL with a "normal" glucose, you likely have early insulin resistance that lifestyle intervention can reverse.

Thyroid: The Most Under-Tested Panel

Standard thyroid screening is just TSH — which misses the majority of thyroid dysfunction. You need the full panel: TSH, Free T3, Free T4, Reverse T3, and thyroid antibodies. A TSH of 3.5 is "normal" but often associated with hypothyroid symptoms. Free T3 is the active hormone — if it is in the lower third of the range, you may benefit from thyroid support even with a normal TSH.

Inflammation Markers

Chronic low-grade inflammation drives virtually every chronic disease. The key markers are hs-CRP (systemic inflammation), homocysteine (cardiovascular and methylation), ESR (general inflammation), and ferritin (which can indicate inflammation even when iron is normal). If hs-CRP is above 1.0 or homocysteine above 8, investigate root causes.

What to Do With Your Results

Once you understand your labs, you can have more productive conversations with your provider and make informed decisions about your health. Tools like BioRoot AI can analyze your full lab panel, flag suboptimal markers, identify patterns your doctor might miss, and generate a personalized protocol to address the root causes.