Citrinin Test

You cannot taste it, smell it, or see it on your food. But if you eat grains, rice, nuts, or red yeast rice supplements, there is a reasonable chance a mold-produced toxin called citrinin is quietly entering your body. Biomonitoring studies across Europe and Asia have found detectable citrinin or its breakdown products in the urine of a large proportion of people tested, including children, pregnant women, and apparently healthy adults.

This urine test measures citrinin itself, a small chemical produced by common food molds. Because citrinin is not something your body makes on its own, any amount in your urine means you have been exposed through what you eat or drink. The primary concern is kidney damage: citrinin's main target is the delicate filtering tissue in your kidneys, and long-term exposure, especially alongside other mold toxins, may contribute to chronic kidney problems.

What Citrinin Is and How It Gets Into Your Body

Citrinin is a mycotoxin, a toxic chemical produced as a byproduct by certain species of mold, specifically Penicillium, Aspergillus, and Monascus fungi. These molds grow on stored grains, rice, corn, sorghum, peanuts, fruits, and cheese. Red yeast rice supplements, which use Monascus mold in their fermentation process, can contain particularly high levels. Europe has recently tightened legal limits on citrinin in these supplements because of the risk.

Once you eat contaminated food, your body absorbs citrinin through the gut. Your liver partially converts it into a breakdown product called dihydrocitrinone (often abbreviated DH-CIT), which is less toxic. Both citrinin and DH-CIT are then filtered out through your kidneys and appear in your urine, which is why a urine test can capture recent dietary exposure. The body clears citrinin relatively quickly, so your urine level primarily reflects what you have eaten in the past few days.

Why Kidney Damage Is the Main Concern

Citrinin's primary toxic target is the kidney. It damages cells in the kidney's filtering tubes by disrupting the energy-producing structures inside those cells (called mitochondria, the tiny power plants in every cell) and by generating harmful unstable molecules that damage cell membranes and DNA. In animal studies and agricultural settings (where livestock consume contaminated feed), chronic citrinin exposure causes visible destruction of kidney tissue. Direct evidence of the same damage in humans is limited, but the mechanism of toxicity is well understood.

Citrinin also affects the liver and, to a lesser extent, the heart and reproductive system, though kidney damage remains the most well-documented concern. The International Agency for Research on Cancer (IARC) classifies citrinin in Group 3, meaning there is not enough evidence to determine whether it causes cancer in humans. However, the combination of citrinin with another common grain mold toxin, ochratoxin A, is a recognized concern for compounding kidney damage, and the two frequently appear together in contaminated food.

How Widespread Is Exposure?

More widespread than most people assume. Biomonitoring studies that tested urine samples from the general population have found citrinin or its breakdown product in a large share of participants across multiple countries.

What this means for you: most average intake levels fall below the provisional "no concern" threshold set by the European Food Safety Authority (EFSA) for kidney toxicity. But subgroups, particularly children and people in regions where rice and grain are heavily consumed, can exceed that level. The fact that exposure is common does not make it safe. It means that without testing, you have no way of knowing where you fall.

Children and Vulnerable Groups

Children consistently show higher exposure levels than adults in the same populations. A German biomonitoring study found higher urinary citrinin concentrations in children compared to adults. A Belgian dietary assessment found that rice consumption poses a particular risk for young children due to high citrinin levels in that food category. In Nigeria, where cereals, nuts, and legumes form a large part of the diet, chronic exposure to citrinin alongside other mycotoxins (aflatoxins and fumonisins) was flagged as a kidney-damage and cancer concern, with children identified as the most vulnerable group.

Pregnant women represent another group of concern. A prospective study of 436 pregnancies in rural Bangladesh examined whether maternal citrinin exposure was associated with adverse birth outcomes such as preterm birth, low birth weight, or pregnancy loss. The combination of citrinin and ochratoxin A exposure showed a trend toward increased low birth weight risk (about 1.8 times higher), but the finding did not reach statistical significance after adjustment for other factors. This is the only prospective study to date examining citrinin and clinical pregnancy outcomes, and it could not confirm or rule out harm.

Co-exposure With Other Mold Toxins

Citrinin rarely acts alone. In contaminated food, it commonly appears alongside ochratoxin A, another kidney-damaging mycotoxin produced by some of the same mold species. The combination is a recognized concern because both toxins target the kidneys, and their effects may compound. Studies in Asia have flagged the co-occurrence of citrinin and ochratoxin A in rice as a public health issue requiring stricter food safety measures.

Multi-mycotoxin biomonitoring panels, like the one this test belongs to, are designed to capture this pattern of combined exposure. Knowing your citrinin level in isolation is useful, but knowing it alongside ochratoxin A and other mold toxins gives you a much more complete picture of your total mycotoxin burden.

Understanding Your Results

This is a newer, specialized measurement without universally standardized clinical cutpoints. No major regulatory body has yet established formal maximum safe levels for citrinin in human biological samples the way they have for cholesterol or blood sugar. The EFSA has set a provisional "level of no concern for nephrotoxicity" based on estimated daily dietary intake, but this is used for population-level risk assessment, not for interpreting an individual urine test result.

What you can interpret clearly: citrinin is not produced by your body. Any detectable level means dietary exposure. A higher level means more exposure. The goal is to be as close to undetectable as possible. Because no formal "optimal" or "elevated" tiers have been published for this specific urine measurement, your lab's detection threshold becomes the practical benchmark. If your result is above the limit of detection, you are absorbing citrinin from your diet.

When Results Can Be Misleading

A single urine sample captures your citrinin exposure over the past few days, not your chronic long-term burden. If you happened to eat a heavily contaminated food item the day before testing, your result may be unusually high. If you ate unusually clean foods that week, your result may be falsely reassuring. Hydration also matters: a very dilute urine sample can produce a lower reading, while a concentrated sample can produce a higher one, even if actual exposure is the same.

Different laboratories use different analytical methods with varying sensitivity. Results from one lab may not be directly comparable to results from another. The most sensitive methods (using a technique called liquid chromatography with tandem mass spectrometry, or LC-MS/MS) can detect even trace amounts of citrinin in urine, while less sensitive methods may miss low-level exposure entirely.

Tracking Your Trend

Because a single urine reading reflects only very recent exposure and can be influenced by what you ate in the prior 48 to 72 hours, serial testing is far more informative than a one-time snapshot. A single elevated reading could be a fluke tied to one contaminated meal. Two or three elevated readings over several months suggest an ongoing dietary source that you need to identify and address.

If you are making changes to reduce exposure, such as switching grain sources, eliminating red yeast rice supplements, or improving food storage, retesting after 2 to 3 months lets you see whether those changes are actually working. The body clears citrinin within days, so a follow-up test should reflect your new dietary pattern, not your old one. Because this marker does not yet have standardized clinical thresholds, your own baseline and trend are the most meaningful reference points. Getting a baseline now and tracking changes over time gives you useful data regardless of where the science eventually sets formal cutpoints.

What to Do if Your Level Is Detectable

A detectable citrinin result is a signal to investigate your dietary sources, not a diagnosis of kidney disease. Start by reviewing the foods most commonly associated with citrinin contamination: rice (especially from certain regions in Asia), corn, sorghum, peanuts, dried fruits, certain cheeses, and red yeast rice supplements. If you take a red yeast rice supplement, this is the single highest-risk source and the easiest to eliminate.

If your citrinin level is persistently elevated across multiple tests, or if your ochratoxin A result on the same panel is also elevated, it is worth checking your kidney function with a basic kidney panel (creatinine, cystatin C, and eGFR). These tests can tell you whether any actual kidney damage is occurring. A nephrologist (kidney specialist) can help interpret the combination of elevated mycotoxin exposure alongside any changes in kidney filtration. For most people, identifying and removing the dietary source will be sufficient to bring levels down.