A client is diagnosed with parathyroid dysfunction. Which serum calcium concentration would support the diagnosis?

A client is diagnosed with parathyroid dysfunction. Which serum calcium concentration would support the diagnosis?

• A. 7.8 mg/dL
• B. 8.9 mg/dL
• C. 9.7 mg/dL
• D. 10.2 mg/dL

Answer: (A)

Parathyroid hormone raises serum calcium, so when parathyroid function is impaired and PTH output drops, calcium in the blood falls (hypocalcemia). The value 7.8 mg/dL is below the normal range (roughly 8.5–10.5 mg/dL) and thus supports a parathyroid dysfunction scenario. The other values are normal or high, which would not reflect decreased PTH. If the issue were hyperparathyroidism, you’d expect elevated calcium, not low.

Parathyroid hormone raises serum calcium, so when parathyroid function is impaired and PTH output drops, calcium in the blood falls (hypocalcemia). The value 7.8 mg/dL is below the normal range (roughly 8.5–10.5 mg/dL) and thus supports a parathyroid dysfunction scenario. The other values are normal or high, which would not reflect decreased PTH. If the issue were hyperparathyroidism, you’d expect elevated calcium, not low.