# How to track lab results over time

> 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 single report answers what your values were that day. A timeline answers whether anything is changing, which is usually the better question.

This is the Markdown version of https://doctano.com/guides/track-lab-results-over-time. The HTML page is the canonical version.

To track lab results over time, compare the same marker, in the same unit, from a comparable lab, under comparable conditions, across at least three dates. Record the value, unit, reference range, lab, and date, and keep the original report. Doctano extracts those fields, normalizes names and units, and places each result on a timeline linked to its source.

## Why one report is not a trend

Two things move a number: a real change in your body and the noise of measurement. Biological variation, sample handling, and differences between assays all contribute. A single reading cannot separate them.

A practical minimum is three results, spread over months or years. Five or more is better. Two readings close together are often just a pair of noisy points.

## What to track

You do not need every value. Track the markers that matter clinically, that your doctor is following, or that you can act on. A timeline of sixty markers is a report. A timeline of ten is a decision tool.

- **Lipids:** LDL cholesterol, non-HDL cholesterol, triglycerides, and ApoB where available.
- **Glucose:** fasting glucose and HbA1c together, not HbA1c alone.
- **Thyroid:** TSH with free T4, and TPO antibodies if they have been measured.
- **Kidney:** creatinine, eGFR, and urine albumin-to-creatinine ratio.
- **Liver:** ALT, AST, ALP, and GGT as a group.
- **Iron and blood:** haemoglobin, ferritin, and transferrin saturation.
- **Vitamins:** vitamin D and vitamin B12, especially if you supplement or have been deficient.

This is an example set, not a prescription. What belongs in your timeline depends on your history and what your doctor is monitoring.

## The four rules of a fair comparison

1. **Same marker.** Make sure two names refer to one test. SGOT and AST are the same enzyme; PCV and haematocrit are the same measure.
2. **Same unit.** Convert before comparing. A value in mg/dL and a value in mmol/L are not two numbers on one chart.
3. **Same lab and method where possible.** A change of lab can look like a change in you.
4. **Same conditions.** Fasting status, time of day, recent illness, and medication changes all move some results.

## What a useful record contains

A row in a spreadsheet or a result in an app should carry more than the number.

- The collection date, not only the report date.
- The value and its unit.
- The reference range printed on that report.
- The lab that produced it.
- A link to the original report.
- A short note: fasting, recent illness, a new medicine, or a changed dose.

## The spreadsheet method, and where it breaks

A spreadsheet is a legitimate way to track results. It is transparent, it is yours, and it can compute anything you know how to ask for. It breaks at the same three points for most people: entering the data, converting the units, and finding the source report later.

### Keep the spreadsheet if

- You follow a small number of markers closely.
- You want custom formulas or charts.
- You will keep entering values after the novelty wears off.
- You already have a clean sheet and it works.

### Use a tracker if

- Your reports span several labs and several years.
- You want the values without typing them.
- You need to get back to the original report.
- You want to ask questions about the history.

## A worked example

A fictional LDL cholesterol history, four reports from the same lab, all fasting.

| Collected | Value | Unit | Range | Note |
| --- | --- | --- | --- | --- |
| 2022-03-12 | 96 | mg/dL | Below 100 | Baseline |
| 2023-04-02 | 102 | mg/dL | Below 100 | Fasting |
| 2024-03-18 | 107 | mg/dL | Below 100 | Fasting |
| 2025-05-09 | 112 | mg/dL | Below 100 | Fasting |

Four readings show a direction that one reading cannot. A rise of 16 mg/dL over three years is not a diagnosis, and it is not nothing. It is a question with evidence behind it, which is exactly what a timeline is for.

## What Doctano does with the history

- **Extracts** the value, unit, range, panel, and date from each report.
- **Normalizes** names and units so a marker stays one marker across labs.
- **Places** every result on the profile's timeline, in date order.
- **Links** each value to the original report.
- **Answers** questions across the history with DoctanoAI, with a pointer back to the source.

## What a timeline still cannot tell you

It cannot tell you why a value moved, whether it needs treatment, or what your target should be. It cannot fix a bad sample or undo a lab error. It gives you a cleaner question for the person who can answer those things.

## Tracking questions

**How often should I track blood test results?**

Follow the interval your doctor recommends for the markers being monitored. The useful part is not the frequency; it is comparing like with like, and keeping enough results to see a direction.

**Can I track results from different labs?**

Yes, with care. Labs can use different methods and units. Doctano normalizes names and units, but a small difference between two labs may still be the assay rather than you. A same-lab comparison is cleaner.

**How many results do I need to see a trend?**

Three is a practical minimum, and more is better. Two readings can show a change but not whether it is a direction. The gap between results matters too: a change over three years is a different signal from the same change in three weeks.

**What should I record from each report?**

The collection date, value, unit, reference range, lab, a link to the original report, and a short note about fasting, illness, or medication changes.

**Is a spreadsheet enough?**

It can be, if you keep it updated and you do not need the source report or unit conversion. It usually stops being enough when the history spans several labs and several years.

## Links

- [Homepage](https://doctano.com/)
- [Lab report tracker](https://doctano.com/lab-report-tracker)
- [How to read a lab report](https://doctano.com/guides/how-to-read-a-lab-report)
- [Organize your reports](https://doctano.com/guides/organize-lab-reports)
- [Reference ranges](https://doctano.com/guides/reference-ranges)
- [All guides](https://doctano.com/guides/)