Aflatoxin Group (B1, B2, G1, G2): What the Number on a Urine Mycotoxin Panel Means

Sample type: Urine

Other names: aflatoxin group, aflatoxin group b1 b2 g1 g2, aflatoxins b1 b2 g1 g2, total aflatoxins, aflatoxin b1, aflatoxin b2, aflatoxin g1, aflatoxin g2, aflatoxin, aflatoxins, af group, mycotoxin aflatoxin

Optimal result: 0 – 0.8 ppb

A raised result means the assay measured aflatoxin at or above 1 ppb — the point at which the laboratory's sample report calls the group Present.

That report does not use one boundary. It sets three categories for this group: Not Present below 0.8 ppb, Equivocal from 0.8 to under 1, and Present at 1 ppb or above. A value of 0.9 is the laboratory declining to call the result either way, which is a different finding from a value of 2, and worth checking which category is printed beside yours.

What a Present result establishes is narrower than it looks. This is one spot sample. Aflatoxins come from fungi on corn, peanuts, cottonseed and tree nuts, and diet is the main source for people not exposed at work — but nothing in the available documentation maps ordinary eating onto these thresholds, so the result cannot tell you whether your diet accounts for the value.

It does not say which of the four was detected, because they are reported together. It does not measure exposure over time; the aflatoxin-albumin adduct in serum is the biomarker used for that. And it does not say where the exposure came from, which is why it cannot attribute anything to a building.

The thresholds it is being compared against are the laboratory's own, not validated ones: no urine mycotoxin reference ranges have been established.

Take the result to the clinician who ordered it, with what you have been eating, your symptoms, and your liver chemistry. A raised result is a reason for that conversation rather than a reason to start a treatment on your own — a 2024 Navy and Marine Corps Force Health Protection Command review notes that acting on unvalidated tests "can lead to misinformation, fear, and unnecessary or inappropriate medical interventions."

A result below 0.8 ppb means the assay did not detect aflatoxin at the level the laboratory calls a finding — the category its sample report labels Not Present.

There is no such thing as too little aflatoxin. These are contaminants from crops rather than something the body needs, so a result the laboratory reports as Not Present is the expected finding and nothing about it needs correcting.

It is worth knowing what it does not establish. This is one spot sample, so it describes a moment rather than exposure over months. The documentation does not establish how long an exposure remains detectable by this assay, so a single Not Present result is not a statement about any longer period.

If the panel was ordered to investigate symptoms, a Not Present result does not explain them either. The symptoms remain worth pursuing with the clinician who ordered the test.

The aflatoxin group line reports four related aflatoxins together as one result in parts per billion, from a competitive ELISA on a urine sample.

Aflatoxins come from fungi on crops — corn, peanuts, cottonseed, tree nuts — and diet is the main source for people not exposed at work, with significant airborne exposure described in industrial and agricultural settings. This is a single spot sample.

The figures beside your result are the laboratory's own categories — Not Present under 0.8 ppb, Equivocal 0.8 to under 1, Present at 1 or above. They are not a reference interval, because none exists: a 2024 Navy and Marine Corps Force Health Protection Command review states that "no urine mycotoxin reference ranges have been established" and that "there is no FDA-approved test for mycotoxins in human urine."

It cannot attribute exposure to a building. Outside rare acute poisonings, the Navy review states that mycotoxin tests "reflect ingestion (food contamination) rather than inhalation"; the AAAAI and the Institute of Medicine concluded the evidence does not support mycotoxin-mediated disease through inhalation in non-occupational settings, and the CDC does not recommend biologic testing of people in water-damaged buildings.

A result reported Present is a measurement, not a diagnosis. Take it to the clinician who ordered it with your diet, your symptoms and your liver chemistry.

At a Glance

This line is not one substance. Aflatoxins are a family, and the panel reports four of them together as one group result in parts per billion.

They come from crops: "a family of toxins produced by certain fungi that are found on agricultural crops such as maize (corn), peanuts, cottonseed, and tree nuts." Diet is the main source for the general population, while significant airborne exposure is described in industrial and agricultural work.

That matters for reading a urine result. This is a single spot sample, so the figure describes one moment. How much an exposure shows up in urine, and for how long, the panel's documentation does not establish.

The range printed beside your result is the laboratory's own reporting cutoff, not a health threshold. A 2024 review by the Navy and Marine Corps Force Health Protection Command states plainly that "no urine mycotoxin reference ranges have been established" and that "there is no FDA-approved test for mycotoxins in human urine."

The practical meaning is narrow: which of the laboratory's three reporting categories your spot sample fell into.

What the panel measures, and how

The RealTime Laboratories panel "screens for 16 mycotoxins using competitive ELISA" from a urine sample. "Results are reported in parts-per-billion (ppb)" and indicate "whether each toxin was present, not present, or equivocal."

Two features of that design shape what your result can say.

It is a group result. B1, B2, G1 and G2 are reported together as one figure, so the report does not give a separate value for each. The documentation does not describe how the group concentration is derived, so the number should not be read as a breakdown of which member was present.

It is an antibody method, not a separation method. A competitive ELISA detects what its antibody binds, which is a different kind of measurement from one that separates and identifies each compound individually.

Where the number beside your result comes from

A reference interval is built by measuring a population and describing where its values fall. No such interval exists here: "no urine mycotoxin reference ranges have been established."

What the laboratory publishes instead is three categories, and its sample report sets them for the aflatoxin group as:

Category Value
Not Present under 0.8 ppb
Equivocal 0.8 to under 1 ppb
Present 1 ppb or above

There is a band where the laboratory declines to call the result either way, so 0.9 is not the same finding as 2. Each toxin on the panel has its own thresholds: ochratoxin A is called present at 2 ppb or above, zearalenone at 0.7, the trichothecene group at 0.09.

The same word on two mycotoxin panels is therefore not the same finding — the aflatoxin pages on this site carry thresholds from three laboratories in two different units.

What a urine aflatoxin result reflects

Something that got into the body — with diet the main route for people not exposed at work.

The Navy review is direct about the inference the test invites, and it scopes the claim: "Except in such acute poisonings, mycotoxin tests reflect ingestion (food contamination) rather than inhalation." It lists ordinary dietary sources — "fruits, vegetables, cheese, or grain products with mold growth, and drinking coffee or wines." On routes generally it is precise: adverse exposure "generally occurs only by ingestion (e.g., aflatoxin in peanuts or heavily contaminated foodstuffs) or with significant airborne exposures in industrial (e.g., waste processing) or agricultural settings (e.g., grain silos)."

Aflatoxin M1 specifically is a metabolite that appears in milk, and it is produced when the liver processes the parent compounds.

This is the part worth sitting with if the test was ordered because of a building. A urine aflatoxin does not trace the toxin to its source, and a home is neither setting where significant airborne exposure is described. What the sources do not establish is how much an ordinary diet should put in a urine sample, so the result cannot tell you whether your value is the expected consequence of eating normally.

How to read your result

Read this against the category printed on your own report.

What your report shows What that establishes What it leaves open
Not Present, under 0.8 ppb The assay did not detect aflatoxin at the level this laboratory calls a finding A spot sample describes one moment
Equivocal, 0.8 to under 1 ppb The value sat in the band the laboratory declines to call either way Everything. It is a statement about the measurement, not about you
Present, 1 ppb or above The assay detected aflatoxin at or above the laboratory's threshold for calling it present Which aflatoxin, where it came from, and whether it matters clinically
Present, and you eat corn, peanuts or tree nuts The same. Diet is a plausible source Whether it explains this value — the assay cannot say what ordinary eating should produce
Present, and the test was ordered because of a building The same. The result does not identify a source Whether the building is relevant at all — this test cannot say
Any category, with liver chemistry outside range Two separate findings on the same person Whether they are connected; that is a clinical question, not one this number answers

No row here is a diagnosis, and no row identifies a source.

If you remember only one thing

The thresholds beside your result were set by the laboratory, not established from a population — and there are three of them, not one, with a band in the middle the laboratory declines to call.

That limits what a single spot sample can carry. Take it to the clinician who ordered it, with what you have been eating and any symptoms, and ask what it changes.

Two people, same result

Two people both have an aflatoxin group result reported as Present on the same panel.

The first eats peanut butter in the mornings and corn products through the week. Diet is an important source, so that is a plausible route — though the assay cannot establish whether an ordinary diet accounts for this value.

The second had the test run after finding mold in a basement and feeling unwell. The number does not distinguish the two. It measures what reached the urine, not where it came from.

Same figure, same panel, and no cause identified either way.

What this result cannot tell you

Where the aflatoxin came from. A urine result carries no information about source.

Whether a building made you ill. This is the inference the test is sold to support — RealTime describes it as measuring "your exposure to mold toxins that standard blood tests miss" — and the evidence does not carry it. The AAAAI and the Institute of Medicine "have concluded that the evidence does not support the position that mycotoxin-mediated disease (mycotoxicosis) occurs through inhalation in non-occupational settings", and the CDC "does not recommend biologic testing of persons who work or live in water-damaged buildings."

Which aflatoxin was detected. The result is a group figure.

How much exposure you have had over time. This is one spot sample; the literature uses the serum aflatoxin-albumin adduct for that question.

Whether your symptoms are explained. Nothing about this number speaks to symptoms.

How your result compares with someone else's. Different laboratories use different methods, units and cutoffs.

Common interpretation mistakes

Reading the thresholds as a reference range. None has been established; they are the laboratory's own.

Reading a detection as a diagnosis. Detecting a compound above a reporting level establishes that it was detected.

Treating the result as evidence about a building. The test measures urine, and outside rare acute poisonings the Navy review states that mycotoxin tests reflect ingestion rather than inhalation.

Comparing a result to another laboratory's. Two panels can use different methods, units and thresholds for the same name.

Reading the group number as one substance. Four are reported together.

Assuming a Not Present result clears anything. It is one sample.

Questions your doctor may ask

What have you been eating — corn products, peanuts, tree nuts, dried fruit?

Who ordered this panel, and what question was it meant to answer?

What symptoms are you having, when did they start, and what makes them better or worse?

Have your liver enzymes been checked, and do you have any known liver condition?

Have you started any supplements or treatments because of this result?

Has anyone else in your household been tested or become unwell?

Read together with

Ochratoxin, Zearalenone, Trichothecene Group and Gliotoxin — the other toxins on the same panel, each with its own thresholds.

Aflatoxin M1 — the metabolite that also appears in milk, reported separately on some panels.

ALT, AST, GGT, Alkaline Phosphatase, Bilirubin and Albumin — liver chemistry that helps assess liver injury and function, and that this panel does not measure.

Alpha-fetoprotein — ordered in liver-cancer surveillance for people who already have a known risk, not as a response to a mycotoxin panel.

Clinical pearls

There is no LOINC code for this result. Codes exist for individual aflatoxins in animal tissue and feed; none covers a grouped aflatoxin in human urine.

The long-term exposure question is answered with a different specimen. The aflatoxin-albumin adduct in serum is the biomarker the literature uses for exposure over extended periods.

Aflatoxin exposure at population scale is a real food-supply concern. The National Cancer Institute notes that "exposure to aflatoxins is associated with an increased risk of liver cancer", while recording that "no outbreak of human illness caused by aflatoxins has been reported in the United States, but such outbreaks have occurred in some developing countries." US food is monitored: the FDA "tests foods that may contain aflatoxins, such as peanuts and peanut butter."

The Navy review notes a specific harm from acting on unvalidated results: they "can lead to misinformation, fear, and unnecessary or inappropriate medical interventions."

Clinical Takeaway

The aflatoxin group line reports B1, B2, G1 and G2 together as one result in parts per billion, from a competitive ELISA on a single spot urine sample. Three properties of that design limit interpretation: it is a group figure giving no separate value per constituent; the specimen is one point in time, with no exposure window established for the assay; and the thresholds are the laboratory's own, because no urine mycotoxin reference ranges have been established and no FDA-approved test for mycotoxins in human urine exists. The sample report sets three categories rather than one boundary — Not Present under 0.8 ppb, Equivocal 0.8 to under 1, Present at 1 or above — so an equivocal value is not a positive. Diet is the main source for people not exposed at work, with significant airborne exposure described in industrial and agricultural settings, and, outside rare acute poisonings, the Navy review states that mycotoxin tests reflect ingestion rather than inhalation — so a result does not attribute exposure to a building. The AAAAI and the Institute of Medicine have concluded the evidence does not support mycotoxin-mediated disease through inhalation in non-occupational settings; the CDC separately does not recommend biologic testing of people who work or live in water-damaged buildings. Aflatoxin exposure is a genuine food-safety concern associated with liver cancer at population scale, monitored in the United States food supply. A result the laboratory reports as Present is a measurement, not a diagnosis, and belongs with the clinician who ordered it alongside diet, symptoms and liver chemistry.

In one sentence

This line reports four aflatoxins together as one group result from a single urine sample, sorted into three categories the laboratory defined, because no reference range for mycotoxins in urine exists.

Bottom line

Your report shows four aflatoxins reported together as one number. They come from fungi on crops — corn, peanuts, tree nuts, cottonseed — and diet is the main source for people who do not work around grain or waste processing.

The figures beside your result are the laboratory's own categories: Not Present under 0.8 ppb, Equivocal from 0.8 to under 1, Present at 1 or above. No reference range for mycotoxins in urine exists and no FDA-approved test for them exists, so those are the laboratory's decisions rather than validated health thresholds. An equivocal value is the laboratory declining to call it, not a positive.

This is one spot sample. It does not say which of the four was found, how much exposure you have had over time, or where it came from — and it cannot connect a result to a building. It also cannot tell you whether ordinary eating explains your value; nothing in the documentation maps diet onto these thresholds.

If the panel was ordered because you are unwell, the symptoms are still worth taking seriously — this number just is not the thing that explains them. Take the report to the clinician who ordered it, with what you have been eating, your symptoms and your liver enzymes, and ask what it changes before starting anything on the strength of it.

Aflatoxin Group: (B1, B2, G1, G2)
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Frequently Asked Questions

What does the aflatoxin group result on a mycotoxin panel mean?
It means aflatoxins B1, B2, G1 and G2 were measured and reported together as one group result in parts per billion, from a urine sample. Aflatoxins are produced by fungi that grow on crops — the National Cancer Institute describes them as "a family of toxins produced by certain fungi that are found on agricultural crops such as maize (corn), peanuts, cottonseed, and tree nuts" — and diet is the main source for people not exposed at work. Because it is a group result, the report gives no separate value for each. Because it is a single spot sample, it describes one moment rather than exposure over time.
What is the normal range for aflatoxin in urine?
There isn't one. A 2024 review by the Navy and Marine Corps Force Health Protection Command states that "no urine mycotoxin reference ranges have been established", and that "there is no FDA-approved test for mycotoxins in human urine." What the laboratory publishes instead is three categories of its own: for the aflatoxin group its sample report sets Not Present below 0.8 ppb, Equivocal from 0.8 to under 1, and Present at 1 ppb or above. Those are decisions about the assay rather than validated health thresholds, and a different laboratory may use different ones, different units and a different method.
Does a positive aflatoxin result mean there is mold in my house?
No. This is the inference the test is sold to support: RealTime describes it as measuring "your exposure to mold toxins that standard blood tests miss." But a urine result carries no information about where the exposure came from, and the Navy review scopes what the test speaks to: "Except in such acute poisonings, mycotoxin tests reflect ingestion (food contamination) rather than inhalation." Outside rare acute poisonings, then, the route is food, with dietary sources including "fruits, vegetables, cheese, or grain products with mold growth, and drinking coffee or wines." The same review is precise about routes: adverse exposure "generally occurs only by ingestion... or with significant airborne exposures in industrial... or agricultural settings" — a home is neither. On the broader question, "the American Academy of Allergy, Asthma and Immunology and the Institute of Medicine have concluded that the evidence does not support the position that mycotoxin-mediated disease (mycotoxicosis) occurs through inhalation in non-occupational settings", and separately the CDC "does not recommend biologic testing of persons who work or live in water-damaged buildings." If there is visible mold or a water leak in your home, that is worth fixing on its own merits — this test is not the evidence for it.
What is the difference between aflatoxin B1, B2, G1 and G2?
They are four members of one family of compounds produced by the same fungi, principally Aspergillus flavus and Aspergillus parasiticus, and they differ in chemical structure. On this panel they are not reported separately — the result is a group figure, so a number on your report does not tell you which of them was detected or in what proportion. Aflatoxin M1 is different again: it is a metabolite, produced when the liver processes the parent compounds, and it also appears in milk.
Where do aflatoxins come from?
Fungi growing on agricultural crops. The National Cancer Institute names maize (corn), peanuts, cottonseed and tree nuts, and notes that exposure also occurs through meat and dairy from animals fed contaminated feed, and that agricultural workers may inhale contaminated dust during crop handling. The main producing species are Aspergillus flavus and Aspergillus parasiticus, which do well in warm, humid conditions. In the United States the food supply is monitored for it: "The U.S. Food and Drug Administration (FDA) tests foods that may contain aflatoxins, such as peanuts and peanut butter."
Is aflatoxin dangerous?
At population scale it is a serious food-safety issue: exposure to aflatoxins "is associated with an increased risk of liver cancer", and that association is why crops and food are monitored. The context for someone in the United States is different from the context in regions where contaminated staples are eaten daily. The National Cancer Institute records that "no outbreak of human illness caused by aflatoxins has been reported in the United States, but such outbreaks have occurred in some developing countries." A single urine measurement the laboratory reports as Present is not the same thing as the sustained high dietary intake those risks are drawn from, and it is not a diagnosis.
What period of time does this result cover?
The honest answer is that the available documentation does not say. The laboratory describes the method and the units but does not publish a look-back window for this assay, and no reference ranges exist against which one could be established. What is known is that this is a single spot urine sample, so it describes a moment rather than a settled level. Research on aflatoxin does use urinary markers for recent exposure and the aflatoxin-albumin adduct in serum for longer periods, but those are specific laboratory biomarkers rather than this commercial panel, and the window shown for one cannot be transferred to the other.
Should I do something about a raised aflatoxin result?
Take it to the clinician who ordered it before acting on it. Bring what you have been eating in the days before the sample, your symptoms, and any liver testing you have had. A result reported Present is a measurement, not a diagnosis, and the same 2024 review warns that acting on unvalidated tests "can lead to misinformation, fear, and unnecessary or inappropriate medical interventions" — which is a reason to have the conversation rather than to start binders, detox protocols or supplements on the strength of the number. If you are unwell, the symptoms are worth pursuing regardless of what this line says.
Clinical Sources & References

All our content is backed by peer-reviewed studies, academic research, and trusted medical sources. We’re committed to accuracy and transparency — see our editorial policy for details.

  1. Urine Mycotoxin Testing
    Navy and Marine Corps Force Health Protection Command · 2024 View source ↗
  2. Aflatoxins — Cancer-Causing Substances
    National Cancer Institute · 2024 View source ↗
  3. Aflatoxin Toxicity
    StatPearls, NCBI Bookshelf · 2023 View source ↗
  4. Mycotoxin Test Panel
    RealTime Laboratories · 2026 View source ↗
  5. Aflatoxin B1 [Mass/mass] in Specimen, LOINC 87584-9
    Regenstrief Institute, LOINC · 2026 View source ↗
  6. Sample Report — Mycotoxin Panel
    RealTime Laboratories · 2026 View source ↗
Article Review Log
Last reviewed September 12, 2026
Originally published September 12, 2026
Reviewed by HealthMatters Editorial Team
Written by Healthmatters Editorial Team
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