Reading Your CBC
CBC — Complete Blood Count
The CBC measures red cells, white cells, and platelets. Most of its value is in spotting what's wrong — anaemia, infection, clotting issues. A few markers (hemoglobin, platelets, RDW) also carry real longevity information when interpreted well.
Hemoglobin — energy and altitude marker
Hemoglobin carries oxygen. Low (<13 for men, <12 for women) suggests anaemia or iron deficit — a common under-diagnosed fatigue cause in menstruating women. High (>17) can suggest dehydration, polycythemia, or sleep apnoea. Aim mid-range for performance.
RDW — the sleeper longevity marker
Red cell distribution width (RDW) measures variation in red-cell size. Elevated RDW (above ~14.5%) independently predicts all-cause mortality in multiple large cohorts — often signalling subclinical nutritional deficits (B12, folate, iron) or chronic inflammation. Almost always overlooked by non-specialist readers.
Match CBC marker to its longevity signal
Connect each CBC component to what it actually tells you.
This step is interactive — open the Thier app to try it.
Neutrophil-to-lymphocyte ratio (NLR) — chronic-stress proxy
NLR is calculated by dividing your neutrophil count by your lymphocyte count from the same CBC differential. It costs nothing extra to compute and serves as a chronic-inflammation + immune-stress marker that's been validated across cancer survival, post-MI prognosis, and ICU outcomes. Optimal: 1.0–2.0. Values above 3.0 — even with all individual components in normal range — flag systemic inflammation worth investigating. Trends over time matter more than a single reading.
Key Takeaway
Most CBCs show everything in the green reference ranges and get waved through. Spend 60 seconds looking at hemoglobin, RDW, MCV, and the neutrophil-to-lymphocyte ratio specifically. Subtle anaemia + nutritional deficits + chronic inflammation hide here and fix easily once spotted.