Synonyms:

• Ca⁺⁺, Ionized, Serum
• Calcium Filterable, Serum
• Calcium Free, Serum
• Calcium Unbound, Serum
• Ionized Calcium, Serum

The Calcium Ionized Serum blood test is used to evaluate nonbound calcium, calcium metabolism, physiologically active calcium fraction, hyperparathyroidism, ectopic hyperparathyroidism. Occasionally useful when hypercalcemia coexists with abnormal protein state such as myeloma. Useful in assessing active calcium fraction in hypoproteinemia and acidosis when calcium is low.