How to track blood test results over time

A blood test report is a snapshot. To compare two snapshots you need the details that explain them, and most of those details are printed on the report. Record these for every result:

• The collection date, not the date the report was issued. Results are compared by when the blood was drawn.
• The marker name as printed. Labs use different names and abbreviations for the same thing, for example ApoB and apolipoprotein B.
• The value and its unit, exactly as printed. The same marker can be reported in mg/dL on one report and mmol/L on another.
• The reference range printed on that report, and which lab it came from. Ranges are set by each lab for its own method, so each one stays with its result.
• Fasting status and time of day, for markers that change with them, such as glucose, triglycerides and cortisol.
• Notes: anything you want to remember about the weeks around the draw, such as travel, illness, a change in training or a new supplement.

The most common reason two results look different is a different unit. Some labs print mg/dL and others print mmol/L, and a few markers are printed in several units across labs. Store each result in the unit on its report and convert only when you compare, so a number you typed can always be checked against the report.

The lab unit converter converts 54 markers between the units labs print and shows the factor it used. The guide to mg/dL and mmol/L explains the arithmetic.

A reference range depends on the lab's method and on the group of people it was set for, so the same result can sit inside one lab's range and outside another's. Copying one range onto every result hides that. Store the range printed on each report next to its value, and read a result against the range from its own report.

Why reference ranges differ between labs explains where the differences come from.

• Use the same lab and method when you can. Different analysers can give slightly different values for the same sample, and a marker such as LDL cholesterol may be calculated by one lab and measured directly by another.
• Use the same conditions. Fasted against fasted, and a similar time of day for markers that change through the day.
• Use the same unit. Convert before comparing.
• Note what changed. A new supplement, an illness or a hard training block can explain a movement that the numbers alone do not.

None of this tells you what a result means. That is a conversation with a qualified clinician.

1. When a report arrives, keep the original PDF somewhere safe.
2. Add the results to your tracker with the collection date, the lab, and the unit and range as printed.
3. Check every value against the report. Typing and PDF reading both make mistakes.
4. Write one line about the weeks around the draw.
5. Compare with the previous draw: the same markers, in the same unit, side by side.

BiomarkerHQ is built around this routine. It reads a text-based lab PDF in your browser on a best-effort basis, shows every extracted value for you to check and edit before anything is saved, and keeps the unit and the range printed on each report. It then draws each marker across your draws against the range from your own report, and a second panel compares two draws side by side.

Wearable data (HRV, resting heart rate, sleep and temperature) can be overlaid on the timeline for context. Without an account, everything stays in your browser, and you can export a JSON backup at any time.