Whole blood mercury testing measures total mercury (organic and inorganic) in whole blood rather than serum. It is the preferred specimen for detecting methylmercury exposure from fish consumption, as methylmercury partitions preferentially into red blood cells. Whole blood mercury provides a more comprehensive picture than serum mercury alone.
Like standard blood mercury testing, whole blood mercury reflects exposure over approximately the preceding 3 months due to methylmercury's half-life in red cells. It is used in occupational health monitoring, dietary assessment of mercury exposure, and in the investigation of potential mercury toxicity symptoms.
FAQs
What is the difference between whole blood and serum mercury?
Methylmercury (from fish) concentrates preferentially in red blood cells, so whole blood mercury better captures dietary organic mercury exposure. Serum mercury is more appropriate for inorganic mercury. For fish-related exposure assessment, whole blood is the preferred specimen.
How long does mercury stay in the blood?
Methylmercury in whole blood has a half-life of approximately 50-70 days, meaning levels reflect the prior 3 months of exposure. After reducing high-mercury fish intake, whole blood mercury falls substantially within 6-12 weeks.
Is whole blood mercury testing widely available?
Yes. Most pathology laboratories can measure whole blood mercury. It requires a specific EDTA whole blood collection tube rather than the standard clotted blood tube used for serum chemistry.
Can fish consumption alone cause mercury toxicity?
In most people, typical fish consumption does not cause mercury toxicity. However, people who eat very large amounts of high-mercury fish regularly (particularly shark, swordfish, orange roughy) can accumulate methylmercury to levels associated with neurological effects. Pregnant women and children are most vulnerable.
