Diethyldithiophosphate (DEDTP)

Pesticides are sprayed on crops, sold for home and garden use, and sometimes linger in food, yet most people never learn whether any of it actually enters their body. A urine test for this marker is one of the few direct ways to catch a recent organophosphate exposure, the family of insecticides behind many of those sprays.

The honest caveat is that this particular marker is faint. Your body clears it within about a day, and it turns up in only a small share of people even in farming communities, so it is most useful as one line in a broader pesticide-exposure readout rather than a verdict on its own.

What This Marker Reflects

DEDTP (diethyldithiophosphate) is one of six breakdown products, known together as dialkylphosphates, that your body makes after contact with organophosphate insecticides. About three-quarters of the organophosphate pesticides registered in the United States form one or more of these six, which is why finding any of them in urine signals exposure to the class as a whole.

What it cannot do is name the exact pesticide. The ethyl-type breakdown products, including this one, come from organophosphates such as chlorpyrifos, diazinon, and parathion, but the test cannot tell which. A positive result can also reflect breakdown products already present in the environment or on food, not only the intact pesticide, so it is a class-level signal rather than proof of a specific dose.

A Snapshot of Recent Contact

Organophosphates are processed and flushed out fast, with these urinary breakdown products largely gone within 6 to 24 hours of absorption. This marker is also harder to pin down because it shows up less often than its cousins, largely because fewer organophosphate pesticides produce it and it tends to appear at lower concentrations rather than because of any instability in the body.

Pregnancy and Birth Weight

The clearest human signals for this specific marker come from pregnancy. In a study of mothers and their newborns, higher levels late in pregnancy tracked with lower birth weight. Each step up in exposure was linked to about 1.4% lower birth weight, within a range of roughly 0.1% to 2.6% lower. The broader evidence tying these breakdown products to birth weight is mixed, though, with some large cohorts finding no association, so treat this as one signal to weigh rather than a settled finding.

Among pregnant agricultural workers, higher levels of this marker were tied to slightly lower Apgar scores, the quick 1-minute and 5-minute checks of a newborn's color, breathing, and responsiveness. The effect was small, but the link held after accounting for other factors.

What this means for you: if you are pregnant or trying to conceive and live or work around pesticide use, this marker offers a way to check whether recent exposure is getting through, information you can act on by changing food sources or reducing contact.

Male Reproductive Hormones

In men from a fertility clinic, higher levels of this marker went along with higher LH (luteinizing hormone) and FSH (follicle-stimulating hormone), the two signals your brain sends to tell the testicles to make testosterone and sperm. A rise in these signals can mean the testicles are being pushed to compensate.

The picture is mixed, though. In the same study, it was the other organophosphate breakdown products, not this one, that lined up most clearly with lower sperm counts and reduced movement. For male fertility, this marker is a supporting clue rather than the headline.

Why It Is Rarely Detected

Across many populations, this marker turns up in only a small minority of people, far less often than the other five in its group, though how often it is detected depends heavily on the lab's method: some national surveys using more sensitive methods have found it in more than half of samples.

Sources: SWAN-MPS (Seo et al., 2024); North Carolina farmworker study (Arcury et al., 2009); urban adult biomonitoring study (Deng et al., 2026).

What this means for you: a non-detectable result is common and does not mean you have avoided all pesticides. It largely reflects that fewer pesticides produce this particular compound, that it appears at lower concentrations than its cousins, and that detection depends on the lab's method. For a fuller exposure picture, it should be read alongside the other five breakdown products, several of which are detected far more often.

Why One Reading Tells You Little

Because your body clears this marker within a day, a single urine sample captures only the last day or so of exposure, which can swing widely from one day to the next. When researchers took repeated samples from pregnant women, this marker showed the least consistency of the six, with a day-to-day agreement score of 0.35, where 1.0 would mean a perfectly stable reading. That instability is the core reason a one-time result is a weak measure of your usual exposure.

If you are trying to understand a real exposure pattern, repeated testing beats a single snapshot. A practical approach is a baseline sample, a repeat if you change your diet or reduce a suspected source, and periodic checks if you live or work where organophosphates are used. Track the direction over time rather than fixating on any one number.

When Results Can Be Misleading

• Timing of the sample: because the marker clears within 6 to 24 hours, a sample taken more than a day after exposure can read as zero even if you were genuinely exposed.
• Low baseline detection: fewer organophosphate pesticides produce this particular compound and it appears at lower concentrations than its cousins, so a low or absent reading can reflect that rather than low exposure. How often it is detected also depends heavily on the lab's method.
• Environmental residues: a positive result can come from breakdown products already on food or in the environment, not only from the intact pesticide, so it does not prove a specific dose.
• Urine concentration: how diluted your urine is shifts the raw number, which is why labs often adjust results to a marker called creatinine.

What to Do With an Unexpected Result

A detectable or rising result is a prompt to look at the whole exposure picture, not to panic over one value. The most useful next step is to measure the full set of six organophosphate breakdown products together, since this one alone is a narrow and unstable window.

Pair the result with your setting: recent produce, home or garden pesticide use, or agricultural work. If you handle pesticides on the job, or if the finding comes up during pregnancy or a fertility workup, an occupational or environmental health clinician can interpret it alongside your exposures and the rest of the panel and help you find and cut the source.