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ionized Ca+2 in blood
Reference values:
- whole blood
- adults: 4.60-5.08 mg/dL (1.15-1.27 nmol/L)
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)
Method: ion-specific electrode
Specimen:
1) whole blood or plasma (heparin)
2) collect blood anaerobically
3) place on ice & deliver to lab immediately
Related
Ca+2
hypercalcemia
hypocalcemia
General
ionized Ca+2 in serum/plasma/blood
References
- Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed.,
W.B. Saunders, 1995
- Mini Panel of 2 tests: Ca Ionized Whole Blood . Ca Ion pH7.4WB
Laboratory Test Directory ARUP: 20140