A nurse is reviewing the laboratory results for four clients. The nurse should recognize which of the following clients has a manifestation of hypoparathyroidism?

A. A client who has a magnesium of 1.8 mEq/L: This value is within the normal range for magnesium, and does not indicate hypoparathyroidism. Low magnesium can affect parathyroid function, but it is not directly related to hypoparathyroidism. B. A client who has a vitamin D of 25 ng/mL: While vitamin D levels are important for calcium regulation, this value is on the lower end of normal and does not directly indicate hypoparathyroidism. Hypoparathyroidism is more related to calcium levels. C. A client who has a calcium of 9.8 mg/dL: This value is within the normal range for calcium, indicating no immediate concern for hypoparathyroidism. Hypoparathyroidism is associated with low calcium levels. D. A client who has a calcium of 5.7 mg/dL: This is a critically low calcium level and is a hallmark sign of hypoparathyroidism. Low calcium levels occur due to insufficient parathyroid hormone (PTH), which is characteristic of this condition.