title: Comparison of serum total calcium, albumin-corrected total calcium, and ionized calcium in 1213 patients with suspected calcium disorders.
abstract: The correlations between serum ionized calcium, serum total calcium, total calcium corrected for albumin and calculated ionized calcium were investigated in a prospective multicentre investigation of 1213 patients suspected of having calcium metabolic disease. Diagnostic discordance between serum total calcium and measured ionized calcium was found in 31% of the patients. With the calculation of albumin-corrected total calcium or calculated ionized calcium the discordance decreased to 17.9%. The diagnostic discordance which could be ascribed to the analytical imprecision (CV = 1.5%) amounted to only 6.7%. Although we found highly significant correlations between the parameters, a considerable scatter around the regression line made prediction of ionized calcium from albumin-corrected total calcium unreliable in many patients.
authors.affiliation: Department of Clinical Chemistry, Herlev University Hospital, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Thode
authors.forename: B
authors.initials: B
authors.lastname: Juul-Jørgensen
authors.forename: H M
authors.initials: HM
authors.lastname: Bhatia
authors.forename: M
authors.initials: M
authors.lastname: Kjaerulf-Nielsen
authors.forename: P D
authors.initials: PD
authors.lastname: Bartels
authors.forename: N
authors.initials: N
authors.lastname: Fogh-Andersen
authors.forename: O
authors.initials: O
authors.lastname: Siggaard-Andersen
mesh_terms: D000465:Algorithms; D002118:Calcium / Q000097:blood*; D006801:Humans; D006934:Hypercalcemia / Q000097:blood; D006996:Hypocalcemia / Q000097:blood; D007477:Ions; D015337:Multicenter Studies as Topic; D011446:Prospective Studies; D011874:Radiometry; D012709:Serum Albumin / Q000032:analysis
chemical_list: D007477:Ions; D012709:Serum Albumin; D002118:Calcium