Test library

Understand the measurement before interpreting the number.

Each guide starts with a direct answer, then shows limitations, context, sources and review status.

Heart health

Apolipoprotein B

Apolipoprotein B (ApoB) is a protein found on cholesterol-carrying particles that can contribute to plaque in arteries. Because each of these particles carries one ApoB molecule, an ApoB blood test helps estimate the number of atherogenic particles—not simply how much cholesterol they contain.

Clinical review pendingRead ApoB guide →
Metabolic health

Hemoglobin A1c

Hemoglobin A1c (HbA1c) is a blood test that estimates average blood glucose over roughly the previous two to three months. It measures the share of hemoglobin with glucose attached and is used for diabetes screening, diagnosis and monitoring in the right clinical context.

Clinical review pendingRead HbA1c guide →
Iron status

Ferritin

Ferritin is a protein that stores iron. A ferritin blood test helps estimate the body's iron stores, but ferritin can also rise with inflammation, infection, liver disease and other conditions. It should not be interpreted as an iron diagnosis by itself.

Clinical review pendingRead Ferritin guide →