Blood Tests & Biomarkers
Know your numbers. What each test measures, healthy ranges, what abnormal results can signal, and which of these are worth asking your doctor about.
A blood test is only as useful as the reading of it. This hub explains what each panel measures, what the reference ranges do and do not mean, and which numbers change a decision.
Two rules apply to everything here. A single out-of-range value is a prompt rather than a diagnosis, and how you prepared for the draw can move the result more than anything happening in your body.
All guides in this hub
Reading your lipid panel: what the cholesterol numbers mean
LDL, HDL, triglycerides and non-HDL in both units. Which number carries the risk, whether you need to fast, and what your result decides.
The testosterone blood test explained: total, free and what your number means
How total and free testosterone tests work, why timing matters, what a result below 300 ng/dL can mean, and which laboratory tests may come next.
Where to start
- The testosterone blood test Total against free, why the time of day matters, and what the number supports.
- Reading your lipid panel Which cholesterol measures predict risk, and what happens if they are high.
- Why am I always tired? The four or five tests worth asking for when tiredness is the reason you are here.
What this hub answers
- When should a testosterone test be taken?
- In the morning and fasted, and confirmed on a second morning before anything is concluded, because levels swing across the day and between days.
- Which cholesterol number matters most?
- LDL and non-HDL cholesterol carry the risk. Total cholesterol on its own hides too much to act on.
- Does one abnormal result mean something is wrong?
- Rarely on its own. Reference ranges are built so that a share of healthy people fall outside them, which is why repeat testing and context come before conclusions.