title: [Validity of routine serum calcium measurements].
abstract: BACKGROUND
  The frequency of diagnosis of primary hyperparathyroidism increased dramatically with the advent of routine serum calcium measurements. The reliability of colorimetric serum calcium measurements is not well known.
  
  
  OBJECTIVE
  To know the frequency of hyper and hypocalcemia in a population of healthy people and the reliability of serum calcium measurements.
  
  
  METHODS
  Serum calcium was measured in 731 subjects participating in a preventive medical examination, using an automated colorimetric method. Serum albumin was also measured. In 31 randomly chosen serum samples, calcium was also measured by atomic absorption spectrometry. Normal serum calcium ranges were established as the mean +/- 1.34 SD of the sample.
  
  
  RESULTS
  Mean serum calcium was 9 +/- 0.7 mg/dl, serum albumin was 4.3 +/- 0.5 g/dl and albumin corrected calcium levels were 8.7 +/- 0.7 mg/dl. Excluding lipemic sera, colorimetric calcium measurement had a correlation of 0.6 with atomic absorption spectrometry and a reliability of 17.9%. Using the proposed normal ranges (7.3-10.6 mg/dl), the frequency of hypercalcemia and hypocalcemia was 0.14 and 0.4% respectively.
  
  
  CONCLUSIONS
  Most subjects found to have hyper or hypocalcemia in this study were asymptomatic.
authors.affiliation: Dpto. de Medicina Interna, Facultad de Medicina, Universidad de la Frontera.
authors.forename: J
authors.initials: J
authors.lastname: Sapunar
authors.forename: L
authors.initials: L
authors.lastname: Quintana
authors.forename: L
authors.initials: L
authors.lastname: Ríos
authors.forename: N
authors.initials: N
authors.lastname: Tapia
authors.forename: M
authors.initials: M
authors.lastname: Villarroel
authors.forename: P
authors.initials: P
authors.lastname: Estrada
authors.forename: R
authors.initials: R
authors.lastname: Fonseca
authors.forename: H
authors.initials: H
authors.lastname: Gudenshwager
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood*; D006996:Hypocalcemia / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
chemical_list: D002118:Calcium
vernacular_title: Validez de la medición rutinaria del calcio sérico.