Abstract
There is wide individual variation in the number of millimoles of calcium bound per gram of albumin in the serum. Individual regression coefficients for serum calcium concentration on serum albumin concentration have been determined in 62 people (25 of our own patients and 37 reported by others). The 95 percentile range was 0-007-0-053 mmol/g, with a median value of 0-025 mmol/g. Accordingly, it is not valid to "correct" a person's measured serum total calcium concentration for variations in serum albumin concentration using an average regression coefficient. Rather, the individual's own regression coefficient must be used. A tourniquet test seems to be the simplest technique for determining this value. Even then, precise interpretation of an individual's corrected serum calcium concentration is possible only when an appropriate reference range for corrected serum calcium concentration has been established. Such an appropriate reference range must be determined from an adequate number of normal people using the individual's own correction factor in each case.
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Selected References
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- Berry E. M., Gupta M. M., Turner S. J., Burns R. R. Variation in plasma calcium with induced changes in plasma specific gravity, total protein, and albumin. Br Med J. 1973 Dec 15;4(5893):640–643. doi: 10.1136/bmj.4.5893.640. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Husdan H., Rapoport A., Locke S., Oreopoulos D. Effect of venous occlusion of the arm on the concentration of calcium in serum, and methods for its compensation. Clin Chem. 1974 May;20(5):529–532. [PubMed] [Google Scholar]
- Marshall R. W., Nordin B. E. Letter: Adjustment of plasma calcium measurements. Br Med J. 1974 Jun 29;2(5921):729–730. doi: 10.1136/bmj.2.5921.729-c. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Payne R. B., Little A. J., Williams R. B., Milner J. R. Letter: Adjustment of plasma calcium measurements. Br Med J. 1974 Jun 1;2(5917):504–505. doi: 10.1136/bmj.2.5917.504-e. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Payne R. B., Little A. J., Williams R. B., Milner J. R. Letter: Correction of plasma calcium measurements. Br Med J. 1974 Mar 2;1(5904):393–393. doi: 10.1136/bmj.1.5904.393-c. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Payne R. B. Serum-albumin in Asians. Lancet. 1973 Aug 18;2(7825):375–375. doi: 10.1016/s0140-6736(73)93214-5. [DOI] [PubMed] [Google Scholar]
- van LEEUWEN A., THOMASSE C. M., KAPTEYN P. C. The determination of protein-bound calcium and magnesium by ultrafiltration-in-vivo with special reference to terminology and method. Clin Chim Acta. 1961 Jul;6:550–565. doi: 10.1016/0009-8981(61)90147-4. [DOI] [PubMed] [Google Scholar]