Office Hours: The Blood Tests That Actually Matter for Your Health

What It Covers

Dr. Mark Hyman explains why standard annual lab panels fail to detect early disease, which specific biomarkers reveal hidden dysfunction years before symptoms appear, and how interpreting results against optimal ranges rather than population-normal ranges produces actionable health intelligence for metabolic, thyroid, cardiovascular, and nutritional status.

Key Questions Answered

• •Optimal vs. Normal Ranges: Standard lab reference ranges reflect two standard deviations from a population mean — meaning 75% of Americans being overweight makes overweight "normal." For fasting glucose, the optimal range is 70–85 mg/dL, not the standard 70–100. Vitamin D should exceed 50 ng/mL, not the lab threshold of 31, to reduce cancer, dementia, and autoimmune risk.
• •Fasting Insulin as Early Warning: Fasting insulin rises before blood sugar or HbA1c becomes elevated, making it the earliest detectable marker of metabolic dysfunction. The reference range ceiling is 18, but optimal is below 5. Insulin creeping from 5 to 10 signals early trouble; above 20 indicates serious insulin resistance requiring immediate dietary and lifestyle intervention.
• •Full Thyroid Panel vs. TSH Alone: Most physicians order only TSH, one of five clinically relevant thyroid markers. A complete panel includes free T3, free T4, reverse T3, and thyroid antibodies. The American College of Endocrinology considers TSH above 3.5 indicative of a slow thyroid. Thirteen percent of Function Health members show elevated thyroid antibodies, most previously undetected and untreated.
• •Advanced Cardiovascular Markers: Standard cholesterol panels miss the two most predictive cardiovascular risk markers: ApoB, which measures the total number of atherogenic particles in circulation, and Lp(a), a genetically determined cholesterol marker requiring more aggressive risk management when elevated. Normal total cholesterol can coexist with high-risk particle composition, making particle number and size testing essential for accurate heart disease assessment.
• •Longitudinal Tracking Over Single Snapshots: A single lab result provides limited context; tracking biomarkers twice yearly reveals directional trends that single readings obscure. Rising triglycerides combined with creeping fasting insulin and elevated hs-CRP together signal prediabetes trajectory years before HbA1c crosses diagnostic thresholds. Tracking against personal baseline, not population averages, identifies individual-specific dysfunction earlier and guides targeted lifestyle interventions.