Relation between total and ionized serum calcium concentrations
- Alan S L Yu, MB, BChir
Alan S L Yu, MB, BChir
- Harry Statland and Solon Summerfield Professor of Medicine
- University of Kansas Medical Center
- Jason R Stubbs, MD
Jason R Stubbs, MD
- Associate Professor of Medicine
- Division of Nephrology & Hypertension
- University of Kansas Medical Center
- Section Editors
- Stanley Goldfarb, MD
Stanley Goldfarb, MD
- Editor-in-Chief — Nephrology
- Section Editor — Mineral and Bone Metabolism; Renal Ureteral Stones
- Professor of Medicine
- University of Pennsylvania School of Medicine
- Mitchell E Geffner, MD
Mitchell E Geffner, MD
- Section Editor — Pediatric Endocrinology
- Professor of Pediatrics
- Keck School of Medicine, University of Southern California
The plasma (or serum) calcium concentration is usually reported in units of mg/dL in the United States, in mmol/L in many other countries, and in meq/L by some laboratories. The relationship between these units is defined by the following equations:
mmol/L = [mg/dL x 10] ÷ mol wt
meq/L = mmol/L x valence
Since the molecular weight of calcium is 40 and the valence is +2, 1 mg/dL is equivalent to 0.25 mmol/L and 0.5 meq/L. Thus, the normal range of total serum calcium concentration of 8.8 to 10.3 mg/dL is equivalent to 2.2 to 2.6 mmol/L and 4.4 to 5.2 meq/L.
DETERMINANTS OF THE SERUM CALCIUM CONCENTRATION
The total serum calcium concentration consists of three fractions [1,2]:To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
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- DETERMINANTS OF THE SERUM CALCIUM CONCENTRATION
- Change in total but not ionized calcium
- - Hypoalbuminemia
- - Hyperalbuminemia
- - Multiple myeloma
- Change in ionized fraction but not total calcium
- - Acid-base disorders
- - Parathyroid hormone
- - Hyperphosphatemia
- MEASURING THE SERUM CALCIUM IN PATIENTS WITH CKD