Single stable reagent (ArsenazoIII) for optically robust measurement of calcium in serum and plasma

J Tony Pembroke, N. O. Leary, P. F. Duggan

Research output: Contribution to journalArticlepeer-review

Abstract

We describe a method based on a single stable reagent for the determination of calcium in serum and plasma with use of Arsenazo III, 200 μmol/L in 50 mmol/L 1,4-piperazinediethanesulfonic acid (PIPES) buffer. The method showed significant positive interference in plasma at pH <6.6 because of the precipitation of fibrinogen, which was eliminated by increasing the pH to 6.8. The assay showed no interference from as much as 600 μmol of bilirubin and 12 g of hemoglobin per liter when applied in a simple monochromatic procedure at 660 nm. The standard curve for calcium was linear from 0 to 5.0 mmol/L. Addition of Intralipid at concentrations >3 g/L demonstrated positive interference, which could be eliminated by using a 700-nm blanking wavelength. The procedure showed good agreement with all-method mean values from two external quality-control schemes.

Original languageEnglish (Ireland)
Pages (from-to)904-908
Number of pages5
JournalClinical Chemistry
Volume38
Issue number6
DOIs
Publication statusPublished - 1992

Keywords

  • Analytical error
  • Fibrinogen
  • Monochromatic and bichromatic assays compared

Fingerprint

Dive into the research topics of 'Single stable reagent (ArsenazoIII) for optically robust measurement of calcium in serum and plasma'. Together they form a unique fingerprint.

Cite this