# What is my normal? The case for a personal baseline

> Doctano turns the lab reports you already have into one private, source-linked health timeline, with an AI that answers from your own results.

A reference range answers a population question. A baseline answers a personal one.

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Your personal baseline is the range your own results occupy over time, measured under similar conditions. Population reference ranges are wide and built from other people, so a result can sit inside the range while being unusual for you. Repeated, comparable results are what make a baseline.

Two people can have the same creatinine and different baselines. A population range cannot tell them apart, because it was not built from either of them.

## A population range is not your range

A reference range usually contains the middle 95 percent of a healthy reference group. That makes it wide by design. It has to cover the usual spread of a population, including people of different ages, sexes, body sizes, and habits.

Inside that width, your own values may sit in a much narrower band. A result that is normal for the population can still be high or low for you, and a result outside the population range can be ordinary for you if it has been stable for years.

## What a baseline is made of

- The same marker, measured consistently.
- The same unit, or a careful conversion.
- The same lab and method where possible.
- Comparable conditions: fasting, time of day, and no recent illness.
- Enough points to see a band, not just one reading.
- Dates, and a note about anything unusual.
- The source report behind each value.

## What moves a value day to day

Biological variation, food, hydration, exercise, alcohol, sleep, infection, medicines, the menstrual cycle, and pregnancy all move some results. The size of the effect depends on the marker. That is why a baseline is more useful when the conditions are similar.

## How to build one

1. Choose the markers that matter to you or that your doctor follows.
2. Keep every report, not only the latest one.
3. Record the collection date, value, unit, range, and lab.
4. Note fasting, illness, or a medicine change beside the value.
5. Review the band once a year, and with your doctor when something changes.

| Element | Why it matters | Practical rule |
| --- | --- | --- |
| Same lab and method | A small assay offset can look like a change | Prefer one lab for a series |
| Same unit | The number changes with the scale | Convert before comparing |
| Fasting | Glucose and triglycerides move after food | Compare fasting with fasting |
| Time of day | Some hormones and iron vary through the day | Sample at a similar time |
| Number of points | Two points are a pair, not a direction | Aim for three or more |
| Context notes | Illness or a new medicine can explain a move | Write it beside the value |
| Source report | The value has to be checkable | Keep the original linked |

## What a baseline can show

A baseline can show a move that is larger than your usual variation, a new value outside your own band, a stable value across years, or a change that coincides with a new medicine. Those are questions to take to a clinician, not conclusions.

## What it cannot show

It cannot tell you the cause of a change, whether a value needs treatment, or what your target should be. A value inside your usual band does not prove you are well, and a value outside it does not prove you are ill. A baseline narrows the question; it does not answer it.

## How Doctano builds the timeline

Doctano normalizes marker names and units, keeps each report's own reference range, and places every result on the profile timeline with a link to its source. It shows the band; it does not diagnose what the band means.

## Baselines, answered

**What is a personal health baseline?**

The range your own results occupy over time when measured under similar conditions. It is built from repeated, comparable results rather than from a population reference group.

**How many results do I need?**

Three is a practical minimum, and more is better. The time between results matters as much as the count: a band over several years is more informative than three samples in one month.

**Can my normal be outside the lab's range?**

Yes. A stable value outside the population range can be your normal, and a value inside it can be unusual for you. That is why the trend and the history matter, not just the flag.

**Does a stable result mean nothing is wrong?**

No. Stability is useful information, but it does not rule out a condition. A clinician reads the pattern with your symptoms, history, and examinations.

**How do I start a baseline?**

Keep the reports you already have, record the date, value, unit, range, and lab for the markers you care about, and add each new report. A tracker or a spreadsheet both work.

## Limits

**A baseline is not a diagnosis.** It describes your own pattern. Ask a qualified professional what a change from that pattern means for you.

## Links

- [Homepage](https://doctano.com/)
- [Lab report tracker](https://doctano.com/lab-report-tracker)
- [Reference ranges](https://doctano.com/guides/reference-ranges)
- [Track results over time](https://doctano.com/guides/track-lab-results-over-time)
- [Borderline results](https://doctano.com/guides/borderline-lab-results)
- [Compare two lab reports](https://doctano.com/guides/compare-lab-reports)
- [All guides](https://doctano.com/guides/)