ROBERT P. HEANEY, M.D.; ROBERT R. RECKER, M.D.
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.
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HEANEY RP, RECKER RR. Estimation of True Calcium Absorption. Ann Intern Med. 1985;103:516-521. doi: 10.7326/0003-4819-103-4-516
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Published: Ann Intern Med. 1985;103(4):516-521.
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Print ISSN: 0003-4819 | Online ISSN: 1539-3704
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