Table 47.2—Typical Laboratory Results in the Differential Diagnosis of Hypercalcemia
|
Laboratory Test |
Primary Hyperparathyroidism |
Humoral Hypercalcemia of Malignancy |
Local Osteolytic Hypercalcemia |
|
Serum calcium |
↑ |
↑ or ↑↑ |
↑ or ↑↑ |
|
Serum phosphate |
↓ or low-normal |
↓ |
↑ |
|
Urine calcium |
↑ |
↑ |
↑ |
|
Parathyroid hormone |
↑ |
↓↓ |
↓↓ |
|
Parathyroid hormone-related peptide |
0 |
↑ |
0 |
NOTE: The diagnosis of malignancy-related hypercalcemia is normally straightforward, and extensive diagnostic testing is rarely required. ↑ = increased; ↓ = decreased; ↑↑ = markedly increased; ↓↓ = markedly decreased; 0 = undetectable.