### Abstract

Measurements of true calcium absorption fraction in women were evaluated to see how closely calculations based on a single measurement of serum specific activity after administration of an oral calcium tracer might approximate the absorption value derived from the full, double-isotope absorption procedure. True absorption, body size, and miscible pool turnover could together explain better than 93% of the variance in serum calcium specific activity values 5 hours after a tracer-labeled test meal. Because measurement of pool turnover is not available routinely, it was dropped from the model, and a predictor equation was developed that allowed estimation of true absorption from the 5-hour serum specific activity value, height, and weight. These variables explained 90.8% of the variance in the 5-hour values and gave estimates of true absorption with a 95% confidence interval of +/- 0.055. This small range of uncertainty makes the procedure useful in estimating absorption efficiency for calcium therapy in routine clinical practice.

Original language | English (US) |
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Pages (from-to) | 516-521 |

Number of pages | 6 |

Journal | Annals of internal medicine |

Volume | 103 |

Issue number | 4 |

State | Published - Oct 1 1985 |

### All Science Journal Classification (ASJC) codes

- Internal Medicine

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## Cite this

*Annals of internal medicine*,

*103*(4), 516-521.