LDL, A1c, Vitamin D & Ferritin: Patient-Friendly Guide

Four lab values come up again and again in conversations about women’s health after 40. Here’s what each one means, why it matters, and what you can do about it — in plain language from a Clinical Laboratory Scientist.

LDL Cholesterol

LDL (“bad” cholesterol) is a key cardiovascular risk marker. But context matters: LDL particle size, HDL levels, triglycerides, and inflammation markers like hsCRP give a fuller picture than LDL alone. A standard lipid panel is a starting point, not the whole story.

HbA1c (Glycated Hemoglobin)

HbA1c reflects your average blood sugar over the past 2–3 months. Normal is below 5.7%. The 5.7–6.4% range indicates prediabetes — a critical window for lifestyle intervention. This is one of the most actionable numbers on a standard lab panel.

Vitamin D (25-OH)

Vitamin D deficiency is extremely common, especially in women over 40. Optimal levels are generally considered 40–60 ng/mL by many functional medicine practitioners, though standard reference ranges vary. Low Vitamin D is associated with fatigue, mood changes, immune challenges, and bone health concerns.

Ferritin

Ferritin is your iron storage protein — and the most sensitive marker for iron deficiency, often becoming low before hemoglobin drops. Low ferritin can cause fatigue, hair loss, and brain fog even when a standard CBC looks “normal.” Always ask for ferritin specifically.

Get your own lab results explained at AskSonya.ai or explore Sonya’s lab literacy books.