ionized Ca+2 in serum/plasma/blood

Specimen: 1) whole blood or plasma (heparin) 2) collect blood anaerobically 3) place on ice & deliver to lab immediately 4) plasma or serum may be stored in a tightly sealed container at 4 degrees C for several days or at -20 degrees C for 6 months Reference values: 1) whole blood -> adults: 4.60-5.08 mg/dL (1.15-1.27 nmol/L) 2) plasma (heparin) -> adults: 4.12-4.92 mg/dL (1.03-1.23 nmol/L) Method: ion-specific electrode Clinical significance: - determines free or biologically active Ca⁺², thus determines 'true' hypercalcemia or 'true' hypocalcemia Increases: 1) clinical disorders a) decreased plasma pH (acidemia) b) primary hyperparathyroidism c) PTH producing tumors (hypercalcemia of malignancy) d) excess intake of vitamin D 2) pharmaceutical agents -> in vivo effects -> hydrochlorothiazide (chronic use), lithium Decreases: 1) clinical disorders a) increased plasma pH (alkalemia) b) increased plasma ionic strength c) primary hypoparathyroidism d) pseudohypoparathyroidism e) vitamin D deficiency f) magnesium deficiency g) major surgery h) trauma i) sepsis j) burns k) pancreatitis l) multiple organ failure m) hemodialysis with low calcium diasylate 2) pharmaceutical agents a) in vivo effects -> anticonvulsants, danazol, foscarnet, furosemide (initial effect), transfusion with citrate- containing products b) chemical interferences -> Ca⁺²-binding agents (EDTA, citrate, oxalate, heparin)

Specific

ionized Ca+2 in blood ionized Ca+2 in serum/plasma

General

special chemistry test

References

Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995
Medical Knowledge Self Assessment Program (MKSAP) 17, American College of Physicians, Philadelphia 2015

Contents

Search