{"id":490,"date":"2023-11-17T11:27:17","date_gmt":"2023-11-17T02:27:17","guid":{"rendered":"https:\/\/lmi.jp\/articles\/?p=490"},"modified":"2026-02-09T14:20:00","modified_gmt":"2026-02-09T05:20:00","slug":"construction-of-new-formula-for-estimating-corrected-caconcentration-the-modified-bromocresol-purple-method","status":"publish","type":"post","link":"https:\/\/lmi.jp\/articles\/2023\/11\/17\/construction-of-new-formula-for-estimating-corrected-caconcentration-the-modified-bromocresol-purple-method\/","title":{"rendered":"Construction of new formula for estimating corrected Caconcentration the modified bromocresol purple method"},"content":{"rendered":"\n

\u2020Naohito Ishii<\/strong><\/em><\/a>, PhD*<\/p>\n\n\n\n

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\u2003<\/span>Cute<\/span><\/i><\/i><\/span><\/summary>
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Ishii N. Construction of new formula for estimating corrected Caconcentration the modified bromocresol purple method. Lab Med Int 2023; 2(2): 17. doi: 10.51041\/lmi.2.2_17<\/p>\n<\/div><\/details>\n<\/div>\n\n\n\n

Editorial
Lab Med Int 2023; 2(2): 17<\/p>\n\n\n\n

\u2020Correspondence: Professor Clinical Chemistry Laboratory, Department of Medical Laboratory Sciences, School of Allied Health
Sciences, Kitasato University, Kanagawa 252-0373, Japan. E-mail: naohito3″@”ahs.kitasato-u.ac.jp
*Associate editor of Laboratory Medicine International; Clinical Chemistry Laboratory, Department of Medical Laboratory Sciences, School of Allied Health Sciences.<\/span><\/p>\n\n\n\n

Download PDF<\/span><\/a><\/div>\n\n\n\n
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See article volume 2: 19-24<\/h2>\n\n\n\n

In this issue of Laboratory Medicine International, Ishigaki et al.\u2019s paper :\u201cA new equation for estimating iCa over a wide range of serum albumin concentrations measured by the modified bromocresol purple method\u201d, has been published. Construction of a new formula for estimating the corrected Ca(cCa) concentration using a modified bromocresol purple(BCP) method is an interesting and clinically important development.
Ionized Ca(iCa) is 50% of the total serum, 40% exists as protein-bound forms, mainly albumin (Alb), and 10% exists as chemically bound forms1)<\/sup><\/strong>. Therefore, serum Ca concentration measurements must be corrected by the serum Alb concentration.
Since the amount of protein-bound Ca decreases in hypoalbuminemia, the serum Ca concentration may not reflect the actual Ca concentration. For this reason, Payne\u2019s formula(cCa(mg\/dL)=tCa(mg\/dL)+4\u2013Alb(g\/dL)) is most commonly used in patients with hypoalbuminemia in Japan2-4)<\/sup><\/strong>. However, because the cCa concentration is only an estimated value of the Ca concentration, it does not reflect the true Ca concentration. A characteristic of iCa is that as the pH decreases, the number of Alb-binding sites in iCa decreases and the ionization rate of Ca in serum increases5)<\/sup><\/strong>.
Ishigaki et al. point out three problems with Paine\u2019s formula: 1) the bromocresol green(BCG) method has cross-reactivity with proteins other than Alb(globulin, C-reactive protein, etc.), 2) iCa is not considered an index , and 3) it is applicable only when Alb concentrations are low.
In this study, a new formula was constructed to estimate the cCa concentration over a wide range of serum Alb concentrations using a modified BCP method corrected to pH 7.4(cCa(mg\/dL)=tCa(mg\/ dL)+0.4(4.6\u2013Alb(g\/dL)).<\/p>\n\n\n\n

Reference<\/h2>\n\n\n\n
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  1. Moore EW. Ionized calcium in normal serum, ultrafiltrates, and whole blood determined by ion-exchange electrodes. J Clin Invest 1970; 49(2): 318-34. PubMed<\/a><\/span><\/li>\n\n\n\n
  2. Payne RB, Little AJ, Williams RB, et al. Interpretation of serum calcium in patients with abnormal serum proteins. Br Med J 1973; 4(5893): 643-6. PubMed<\/a><\/span><\/li>\n\n\n\n
  3. Payne RB, Carver ME, Morgan DB. Interpretation of serum total calcium: effects of adjustment for albumin concentration on frequency of abnormal values and on detection of change in the individual. J Clin Pathol 1979; 32(1): 56-60.PubMed<\/a><\/span><\/li>\n\n\n\n
  4. Fukagawa M, Yokoyama K, Koiwa F, et al. Clinical Practice Guideline for the Management of Chronic Kidney Disease-Mineral and Bone Disorder. Ther Apher Dial 2013; 17(3): 247-88.PubMed<\/a><\/span><\/li>\n\n\n\n
  5. Wang S, McDonnell EH, Sedor FA, et al. pH effects on measurements of ionized calcium and ionized magnesium in blood. Arch Pathol Lab Med 2002; 126(8): 947-50.PubMed<\/a><\/span><\/li>\n<\/ol>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"

    \u2020Naohito Ishii, PhD* EditorialLab Med Int 2023; 2(2): 17 \u2020Correspondence: Professor Clinical Chemistry Laborat […]<\/p>\n","protected":false},"author":1,"featured_media":2072,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"swell_btn_cv_data":"","footnotes":""},"categories":[61,57],"tags":[64,62],"class_list":["post-490","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-editorial-lab-med-int-2023-22","category-lab-med-int-2023-22","tag-lab-med-int-2023-22-17","tag-naohito-ishii"],"_links":{"self":[{"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/posts\/490","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/comments?post=490"}],"version-history":[{"count":9,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/posts\/490\/revisions"}],"predecessor-version":[{"id":934,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/posts\/490\/revisions\/934"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/media\/2072"}],"wp:attachment":[{"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/media?parent=490"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/categories?post=490"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lmi.jp\/articles\/wp-json\/wp\/v2\/tags?post=490"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}