Quicksilver Scientific is bringing its information-rich mercury speciation analysis to the people - literally. QS recieved its temporary CLIA number in June of 2009 and will offer a suite of analyses in human blood, hair, and urine. This suite of tests not only gives the best available representation of a persons body burden of all forms of mercury, but also shows how efficient their excretion of these forms is. For example, for a certain level of inorganic mercury in the blood, there should be about a 7 times higher level in the urine (based on the average of a healthy population); however test subjects with the highest blood inorganic mercury levels had a much lower than expected level in the urine (less than a 7:1 ratio), indicating that a deficiency in excretion ability is leading to accumulation in the body. A similar relationship exists for blood methylmercury and hair mercury. These ratios give much-needed guidance to clinicians who are trying to lower a patients burden of toxic mercury.

This suite of analyses makes the former practice of “Challenge Testing” (taking a pharmaceutical chelating compound to increase urinary mercury elimination) obsolete. Challenge testing was truly a “black box” approach that did not reveal anything about the form of mercury present in the body, and worse still, the different agents used for challenge testing (EDTA, DMSA, DMPS) had very different efficiacies for different forms, leading to a very muddy interpretation of results. For example DMSA is not efficient for inorganic mercury and thus will only yield high results if there is alot of methylmercury present - thus a tuna-eater with no amalgams will show high while a fish-abstainer with a mouth full of amalgmas will show low, leading to a completely off-base analysis of mercury burden.

Challenge testing was also incorrectly promoted as an indicator of body burden beyond what non-challenged testing could offer; this idea seemed to persist despite clear research showing that the results reflected predominantly blood levels with a bit of kidney burden as well. If only using total mercury testing perhaps this was the best route, but with a full suite of speciation testing far more information is available than from a conventional challenge test, and the patient is not put through a potentially “challenging” procedure (i.e. if the kidneys are already damaged and not filtering well, why force more blood-borne mercury into them?…and if it does not come out the weakened kidneys, then where does it go?).

Keep tuned for more information on human biomonitoring with mercury speciation testing!