Department of Clinical Biochemistry, Leeds Teaching Hospitals NHS Trust, and Department of Research & Development, Leeds University, Leeds, UK.
Ann Clin Biochem. 2012 Jul;49(Pt 4):352-8. doi: 10.1258/acb.2011.011060. Epub 2012 Apr 25.
Calcium exists in human blood in a free form and in a form bound to plasma proteins, principally albumin. Since it is the ionized form that is biologically active, it has long been common practice to present calcium adjusted on the basis of serum albumin concentration. The concept of adjusted calcium has only been evaluated in adults. In this study, we evaluated the use of the adult-adjusted equation to report calcium in children.
We searched the laboratory information system over three teaching hospitals for young patients aged between newborn and 18 years old with a request for calcium and albumin analysis but with no evidence of disturbances of calcium homeostasis. These data were organized on the basis of age and was separated into four age groups (birth to 1 month old, 1 month to 1 year old, 1 to 5 years old and 5 to 18 years old). These data were subjected to regression analysis to derive the calcium-adjusted equation for each age group.
There is an inverse relationship between the bias value and the age. The younger the age, the higher the difference between the adjusted calcium calculated by the adult equation and that calculated by the age-specific equation. This pattern was maintained on all sites.
For all sites, the adult-adjusted calcium equation may be used to calculate the adjusted calcium for children aged one year old and above.
钙以游离形式和与血浆蛋白（主要是白蛋白）结合的形式存在于人体血液中。由于只有离子形式具有生物活性，因此长期以来，根据血清白蛋白浓度调整钙的做法很常见。调整钙的概念仅在成人中进行了评估。在这项研究中，我们评估了使用成人调整公式来报告儿童的钙值。
我们在三家教学医院的实验室信息系统中搜索了年龄在新生儿至 18 岁之间、有钙和白蛋白分析请求但无钙稳态紊乱证据的年轻患者的实验室数据。这些数据根据年龄进行组织，并分为四个年龄组（出生至 1 个月、1 个月至 1 岁、1 至 5 岁和 5 至 18 岁）。对这些数据进行回归分析，得出每个年龄组的钙调整公式。
偏倚值与年龄呈反比关系。年龄越小，成人方程计算的校正钙与特定年龄方程计算的校正钙之间的差异越大。这种模式在所有站点都得到了维持。
对于所有站点，成人调整钙公式可用于计算 1 岁及以上儿童的校正钙。
