A nurse reviews the laboratory report for a client who is receiving lithium three times daily PO. The client's current blood lithium level is 1.8 mEq/L. The nurse identifies that this lab value indicates which of the following?

A. A level of 1.8 mEq/L is too high for initial treatment, as it is above the therapeutic range. B. A level of 1.8 mEq/L is not within the maintenance treatment level, which is typically 0.6–1.2 mEq/L. C. The level is above the therapeutic level, not below it. D. A lithium level of 1.8 mEq/L is above the therapeutic range (0.6–1.2 mEq/L) and is considered toxic. Toxicity can lead to serious side effects like tremors, confusion, and renal dysfunction.