# Aflatoxin urine test: what it measures, sources and limits

Source page: https://intrinsicprism.com/learn/markers/aflatoxin-urine-test

Last updated October 2026

An aflatoxin urine test measures aflatoxins, mycotoxins made by certain Aspergillus molds. WHO says aflatoxins are amongst the most poisonous mycotoxins and frequently affect cereals, oilseeds, spices and tree nuts. A result shows recent exposure; it does not name the source or diagnose illness.[[1]](#source-1)

## Key facts

Aflatoxins: key facts, checked October 2026.

| Item | Detail |
| --- | --- |
| Markers | Aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1, aflatoxin G2 and aflatoxin M1[[2]](#source-2) |
| Sample (as listed on What we Test) | Urine[[2]](#source-2) |
| Panel group | Mycotoxins (29 listed); aflatoxins: 5[[2]](#source-2) |
| Molds that make them (WHO) | Aspergillus flavus and Aspergillus parasiticus[[1]](#source-1) |
| Crops often affected (WHO) | Cereals (corn, sorghum, wheat, rice), oilseeds (soybean, peanut, sunflower, cotton seeds), spices and tree nuts[[1]](#source-1) |
| Aflatoxin M1 | Found in milk of animals fed contaminated feed (WHO); also formed when the body processes AFB1[[1]](#source-1)[[2]](#source-2) |
| Part of | Intrinsic Prism at-home test: 133+ markers, HSA/FSA eligible[[3]](#source-3) |
| Analyzed by | A CLIA-certified, CAP-accredited US laboratory[[3]](#source-3) |

The Intrinsic Prism at-home test is $1,999 per participant; see [how to order](https://intrinsicprism.com/buy).

## What are aflatoxins?

WHO says aflatoxins are amongst the most poisonous mycotoxins and are produced by certain moulds (Aspergillus flavus and Aspergillus parasiticus) which grow in soil, decaying vegetation, hay and grains.[[1]](#source-1)

## Where does exposure come from?

Food is the documented route. WHO lists cereals (corn, sorghum, wheat and rice), oilseeds (soybean, peanut, sunflower and cotton seeds), spices (chili peppers, black pepper, coriander, turmeric and ginger) and tree nuts (pistachio, almond, walnut, coconut and Brazil nut); aflatoxin M1 can be found in the milk of animals fed contaminated feed.[[1]](#source-1) A water-damaged building is a separate question that a urine result cannot answer on its own.

## What are the health concerns?

WHO says large doses of aflatoxins can lead to acute poisoning (aflatoxicosis), usually through liver damage, that aflatoxins are genotoxic and cause cancer in animal species, and that there is also evidence they can cause liver cancer in humans.[[1]](#source-1)

## How to test for aflatoxins at home

Order the Intrinsic Prism test online, collect your samples at home with the kit, and a courier picks them up.[[3]](#source-3) The test lists five aflatoxins (B1, B2, G1, G2 and M1) among 29 mycotoxins, inside a 133+ marker test. [[2]](#source-2)

## What can and can't a result tell you?

### It can

- Show recent aflatoxin exposure and the pattern across the five listed forms.[[2]](#source-2)

### It can't

- Diagnose aflatoxicosis or identify one food or building source.[[2]](#source-2)
- Reflect long-term exposure; urine reflects a limited exposure window.[[2]](#source-2)

A measured level shows exposure. It does not by itself mean the chemical is causing disease.[[4]](#source-4) Results are educational and are not a diagnosis; review them with a clinician.

## Related pages

- [At-home mycotoxin test](https://intrinsicprism.com/learn/at-home-mycotoxin-test)
- [Ochratoxin A (OTA) urine test](https://intrinsicprism.com/learn/markers/ochratoxin-a-urine-test)
- [What a positive mycotoxin test means](https://intrinsicprism.com/learn/positive-mycotoxin-test-meaning)
- [Mycotoxins on What we Test](https://intrinsicprism.com/what-we-test#mycotoxins)
- [All marker guides](https://intrinsicprism.com/learn/markers)

## Frequently asked questions

Which aflatoxins are in the Intrinsic Prism test?
:   Five: aflatoxin B1, B2, G1, G2 and M1, measured in urine.[[2]](#source-2)

Where do aflatoxins come from?
:   WHO lists cereals, oilseeds, spices and tree nuts affected by Aspergillus molds; aflatoxin M1 can be found in milk from animals fed contaminated feed.[[1]](#source-1)

Does a positive aflatoxin result mean my house has mold?
:   Not necessarily. WHO describes aflatoxins mainly as food contaminants, and a urine result cannot identify the source on its own.[[1]](#source-1)[[2]](#source-2)

## Sources

Last updated October 2026. Prepared by the Intrinsic Prism team. Educational, not medical advice. Every agency source below was fetched and read in October 2026. This page is general information, not legal or medical advice.

1. [[1] Mycotoxins fact sheet | World Health Organization](https://www.who.int/news-room/fact-sheets/detail/mycotoxins) Fetched and checked October 2026.
2. [[2] What we Test | Intrinsic Prism (marker directory)](https://intrinsicprism.com/what-we-test) Read from the live site October 2026.
3. [[3] Intrinsic Prism homepage (price, HSA/FSA and collection statements)](https://intrinsicprism.com/) Read from the live site October 2026.
4. [[4] About the National Exposure Report | CDC](https://www.cdc.gov/environmental-exposure-report/about/index.html) Fetched and checked October 2026.