Nail testing: what to do when hair isn't there.

When nail testing is the right call.

When hair isn't available. Head hair too short to cut. A shaved head. Body hair that can't be collected, or that the donor won't consent to. In those situations the choice isn't hair versus nails — it's nails versus nothing.

When the case needs to reach back further than head hair covers. Head hair gives about ninety days. A fingernail gives three to six months, and a toenail can reach twelve — the same ground body hair covers, without needing body hair.

When a contact challenge is likely. This is the argument most people miss. A nail can pick up a substance the hands touch, so fingernail results are open to a handling explanation. Toenails are not — they spend the day inside socks and shoes and don't touch anything. If a result is likely to be contested on exposure grounds, a toenail is the harder specimen to argue with.

That last point is a decision made when the order is written, not at the collection site.

Where nail testing is weaker than hair.

Two limits matter, and the first one surprises people.

Ingestion takes longer to show up. After someone takes a substance, it can be one to two weeks before it's detectable in nail. Hair's equivalent lag is about five to seven days. So if a case turns on something recent, nails are the weaker instrument — not the stronger one.

Contact is a different route in. Nails are exposed to whatever the hands touch, so a substance can reach a fingernail from handling as well as from use — and unlike ingestion, that transfer isn't delayed.

Two steps address it. Before clipping, the donor washes their hands, removes any nail polish, and cleans under the nails, with the collector observing. At the laboratory, the specimen is washed again before analysis to remove surface contamination.

That's a documented process, and it's more than most people assume happens. It still doesn't settle every case. Whether contact explains a particular result is a question for the case, and in some instances the laboratory data can speak to it. It isn't a question we answer.

This applies to fingernails. A toenail doesn't touch what the hands touch, which is why it's the stronger specimen where a contact argument is expected.

And the timeline is imprecise. Like body hair, a nail result speaks to a span rather than a sequence. It can't place a substance on a particular date within the window.

How a nail collection works.

The donor clips their own nails, in view of a trained collector, who then takes custody of the specimen immediately. Clippings come from all ten fingernails or all ten toenails.

That's a real difference from hair, and worth being direct about: on a hair collection the collector cuts the sample; on a nail collection the donor does the cutting while the collector observes. The specimen is under observation from the first clipping and sealed under an unbroken chain of custody from the moment it's handed over.

Before clipping, the donor washes their hands, removes any nail polish, and cleans under the nails. The collector observes that too. At the laboratory the specimen is washed again before analysis.

Fingernails and toenails are both collectable, and they are not interchangeable. A fingernail covers roughly three to six months; a toenail can reach twelve. Availability matters — whichever are long enough to clip — but so does the window the case needs and whether a contact argument is expected. Where it matters, the order should name which.

We collect nails at our Elk Grove Village office and arrange nail collections nationwide through the same network we use for hair collections.

The practical problem: there has to be enough nail.

This is the constraint that stops more nail collections than anything else, and it's worth raising before an order is drafted rather than after.

The laboratory needs a clipping of about two to three millimetres from each of all ten nails — a little thicker than a quarter. More for larger panels.

Plenty of people don't have that, and men frequently don't. Someone who keeps their nails short has nothing to clip, and unlike hair there's no equivalent fallback within the same specimen — the answer is to wait for growth, which can mean weeks.

Which is why an order directing testing should also direct that nails not be cut before collection, the same way it directs that hair not be cut or treated. Our court order language covers both.

One more practical constraint.

Not every collection site keeps nail clippers on hand — it's a less commonly ordered test, and a site set up for urine and hair may not stock the supplies. We can overnight what's needed, which adds a day or two.

That delay matters less here than it would elsewhere. The window is months; a two-day wait doesn't move it. But it's worth knowing in advance rather than discovering at the site, which is another reason to call before a collection is scheduled rather than after.

Panels and the detection window.

The same panels available for hair run on nails, from a basic five-substance panel up to eighteen. Alcohol (EtG) can be added.

Which one fits depends on what's alleged — and where there's a court order, on what the order names. A panel that doesn't reach the substance actually at issue is the most common way this testing gets wasted.

Detection window — fingernail roughly three to six months; toenail up to about twelve. That applies to alcohol (EtG) the same as to drugs and their metabolites.

What a nail result can't establish.