This post used to argue that blood tests miss most metal burden because metals leave the blood within hours or days and hide in tissue, so you need hair analysis, an organic acids test, or a provoked urine test instead. When I checked it, most of that didn’t hold. The standard tests are better than I said, and the alternatives are weaker. What changed is on the corrections page.
The metals that matter, and the test that fits each
Most people’s exposure is low. The usual reasons to test are a specific source: a job (battery work, soldering, demolition, some dentistry, smelting), stripping old lead paint, old lead pipes, a lot of large predatory fish, some imported remedies and cosmetics, or a hobby such as shooting or stained glass.
So the question isn’t whether blood and urine tests “look in the wrong place”. It’s which ordinary test fits the metal and the source. Your GP or an occupational health service can order these, and confirmed poisoning is a medical matter.
Provoked urine testing: why I don’t use it
In a provoked test, a chelating drug (DMSA, DMPS or EDTA) is given, then urine is collected. Chelators raise urine metals in almost everyone, including people with ordinary exposure, and the result is compared against ranges set from unprovoked urine, so “elevated” is close to guaranteed. The American College of Medical Toxicology recommends against it (ACMT 2017), and chelating drugs carry real risks. Grade: not valid for diagnosis. Chelation, when it’s genuinely needed, is a hospital treatment for confirmed poisoning.
Hair analysis (HTMA): what it can and can’t do
I offer hair tissue mineral analysis, so this section is the one where I have the most reason to be generous. I’ll try not to be.
Hair is easy to collect and grows about a centimetre a month, so a sample near the scalp reflects the last couple of months. That’s the appeal. The problem is reliability. When researchers split one person’s hair sample and sent it to six US hair-analysis labs, the highest and lowest results differed more than tenfold for 12 minerals, and the authors recommended that practitioners not use hair analysis to assess nutritional status or suspected environmental exposure (Seidel 2001). It was one sample in 2001, but I haven’t found a better study showing hair results track body levels for most minerals.
- Contamination. Shampoos, dyes, bleaching, swimming pools and dust all get into hair. An unusual metal result needs checking against your history before anyone acts on it.
- A low result doesn’t rule anything out, and a high one doesn’t confirm it. Confirm a raised toxic metal with the ordinary blood or urine test above.
- The “displacement” ratios. The biology behind them is real: lead mimics calcium and is stored in bone; cadmium competes with zinc; mercury binds selenium tightly. What hasn’t been shown is that reading those relationships off hair ratios tells you what’s happening in your body. Grade: mechanistic; the hair readings are untested.
- Convenience is real. For someone who can’t face a blood draw or a stool kit, hair is easier. That makes it accessible, not accurate, and it can’t stand in for a GI-MAP, a DUTCH test or blood chemistry.
As a conversation starter about minerals and exposure, read alongside your history and diet, with anything that matters confirmed in blood or urine. Not as a measure of “toxic burden”, and not as a reason to start a detox or chelation protocol. Grade: unreliable as a stand-alone measure (Seidel 2001).
Organic acids tests (OAT): no metal marker
An OAT doesn’t measure metals. I used to say that a raised pyroglutamate (a sign the body’s glutathione recycling is strained) plus a few other markers was “often the first functional signal” of metal toxicity. Pyroglutamate can rise for many reasons, including long-term paracetamol, poor nutrition, serious infection and some antibiotics (Weiler 2015), and no OAT pattern has been validated as a sign of metal exposure. Grade: none, as a metal marker. If a metal is the question, test the metal.
What I’d do
- Start with history. Your job, your house (age, paint, pipes, renovation), fish intake, smoking, remedies and cosmetics, hobbies. That decides whether testing is worth it at all.
- If there’s a plausible source, use the ordinary test for that metal: blood lead, blood or urine mercury, urine cadmium, speciated urine arsenic, through your GP or occupational health.
- Reduce the source. That does more than anything else: stop the exposure, and stop smoking.
- Don’t chelate or “detox” on the strength of a hair, OAT or provoked result. Binders can’t pull metals out of your tissues (what binders can and can’t do).
Metals are a real, specific hazard, not a general explanation for fatigue, brain fog or aches. Those symptoms have many causes, and they deserve a proper look at all of them.