# How to change units and choose a reference range source in Health3

> Another unit for one biomarker, and the reference range from another published source. A narrated 0:33 walkthrough with captions, chapters and a transcript.

*Source: [https://www.health3.app/videos/change-units-reference-source/](https://www.health3.app/videos/change-units-reference-source/)*

Published October 27, 2026Video guide, 0:33

Another unit for one biomarker, and the reference range from another published source.

Narrated, real app screens with synthetic demo data. Captions in English and 24 more languages.

## Chapters

1. [0:00](https://www.health3.app/videos/change-units-reference-source/?t=0) Biomarker page
2. [0:05](https://www.health3.app/videos/change-units-reference-source/?t=5) Change Unit
3. [0:13](https://www.health3.app/videos/change-units-reference-source/?t=13) Reference Ranges
4. [0:21](https://www.health3.app/videos/change-units-reference-source/?t=21) Select a source
5. [0:27](https://www.health3.app/videos/change-units-reference-source/?t=27) Back to default

## What the video shows

A narrated walkthrough of the Health3 iPhone app with synthetic demo data: Change Unit converts the chart, the range and the values of one biomarker, and Reference Ranges lists ranges from different sources with the sex and age each applies to; selecting a source makes it the range used across the app.

Written guide: [Review the source behind a biomarker reference range](https://www.health3.app/features/multiple-reference-ranges/).

## Transcript

1. 0:00 Each biomarker page has its own unit and reference range settings.
2. 0:05 Change Unit switches to another unit. The chart, the range and the values convert, and the choice is kept for this biomarker.
3. 0:13 Reference Ranges lists ranges from different sources, with the sex and age each one applies to.
4. 0:21 Selecting a source makes it the range used across the app. The default is marked.
5. 0:27 Selecting the active source again returns to the default.

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Real Health3 iPhone screens with synthetic demo data and a synthetic narrator voice. Health3 organizes lab results; it does not interpret them or give medical advice. Some features require Premium.