"Blood: For people who eat large quantities of fish and , the mercury concentration ratio of to (serum) is approximately 10:1, and most mercury contained in the red blood cells is in the form of ; therefore, methylmercury exposure can be evaluated by measuring total mercury in blood. It is believed that 50% of inorganic mercury is present in the plasma and the mercury concentration in the plasma increases in relation to the amount of inorganic mercury accumulated in the kidneys."