"Another commonly available test is blood or urine pyruvic acid. Pyruvic acid can be elevated for a number of reasons, but mercury is notorious for interfering with the mitochondrial pyruvate dehydrogenase complex, where it binds to and deactivates the lipoic acid coenzyme, resulting in elevated pyruvic acid."
My sons Pyruvate was very low, however there were still tests that showed mercury damage. The mercury was the highest toxic element in the hair analysis, but again I believe a urine challenge test will show that there's alot more.