All Guides
Lab Testing, Explained
Evidence-based guides across every major testing category. No jargon, no sales pitch — just the science.
Looking up a specific term? See the glossary →
Thyroid Function Tests Explained: TSH, T4, T3, and Antibodies
TSH, Free T4, Free T3, TPO, TgAb — what each test measures and why "subclinical" thyroid dysfunction matters.
Understanding Your Lipid Panel: LDL, HDL, Triglycerides, and Beyond
Cholesterol is more nuanced than LDL vs. HDL. This guide covers particle size, ApoB, Lp(a), and what your numbers actually tell you.
Complete Guide to Blood Panel Tests: What to Ask Your Doctor
A walkthrough of every standard blood panel — CBC, CMP, lipid panel, thyroid panel — with the exact questions to ask your provider.
Why Your Cholesterol Test Is Missing the Most Important Number
Your standard lipid panel tells you your LDL cholesterol. It does not tell you how many LDL particles are actually floating through your bloodstream. That number — apolipoprotein B, or ApoB — is what the 2026 ACC/AHA guidelines now specifically recommend for millions of Americans whose LDL looks fine but whose cardiovascular risk is not.
Vitamin D Testing: What 25(OH)D Actually Tells You
If your doctor ordered a "vitamin D test," there is a roughly 50% chance they checked the wrong metabolite — or ordered a test you did not need in the first place. Here is what the numbers mean — without the hype.