Blood mercury:
Blood mercury concentrations rapidly increase immediately after or during exposure. Therefore, measurements should take place right after exposure. However, in cases of chronic exposure, blood mercury concentration levels will still likely remain high for weeks or months. Normally, whole blood mercury is below 2 ng/mL. Historically, dentists and those with industrial mercury exposure have shown levels that are 35% higher.
Urine mercury:
The correlation between mercury excretion in the urine and clinical symptoms is considered poor. Urine mercury is thought to be more useful in the analysis of elemental (inorganic mercury) exposure events, though urine testing likely detects a mixture of both dietary methylmercury and elemental mercury. Daily urine excretion of mercury above 50 μg/day indicates significant exposure (per World Health Organization standard).
Hair and nail mercury:
As with lead, if mercury is absorbed it can bind to many proteins, including keratin. Hair and nail analysis can be used to document the time of peak exposure if the event was in the past.
