Ionized calcium: serum levels during symptomatic hypocalcemia.
The concentration (activity) of ionized calcium in serum [Ca-++] was measured in nine patients with symptomatic hypocalcemia of diverse etiology. In all nine patients the [Ca-++] was smaller than or equal to 2.50 mg/dl. No significant correlation was found between the [Ca-++] and serum levels of either total calcium or phosphate. Use of the McLean-Hastings nomogram failed to reveal any significant statistical correlation between the predicted [Ca-++] values and those actually measured. These data indicate that: (1) symptomatic hypocalcemia occurs when levels of ionized calcium in serum fall near or below a critical threshold concentration of 2.50 mg/dl and (2) the [Ca-++] must be measured directly to confirm the clinical impression of hypocalcemia.
D000136:Acid-Base Equilibrium; D000293:Adolescent; D000328:Adult; D001798:Blood Proteins / Q000032:analysis; D001803:Blood Transfusion; D002122:Calcium Chloride / Q000097:blood; D002675:Child, Preschool; D006801:Humans; D006996:Hypocalcemia / Q000097:blood* / Q000175:diagnosis; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood*; D007477:Ions; D008274:Magnesium / Q000097:blood*; D010710:Phosphates / Q000097:blood*; D012709:Serum Albumin / Q000032:analysis
D001798:Blood Proteins; D007477:Ions; D010710:Phosphates; D012709:Serum Albumin; D008274:Magnesium; D002122:Calcium Chloride