DETERMINATION OF INTESTINAL STRONTIUM ABS ORPTION - ASSESSMENT AND VALIDATION OF ROUTINELY MANAGEABLE TEST PROCEDURE

Intestinal strontium absorption has been discussed recently as an indi rect measure for calcium uptake. Prerequisite for the clinical use of an oral strontium test is the availability of a reliable procedure inc luding controlled strontium supply, sample pretreatment and analysis a s well as the assessment of normal values. In the present study, a gro up of young females (n = 33; 24.0 +/- 2.7 y; BMI 21.5 +/- 1.9) receive d an oral dose of 2.27 mmol strontium in a standardized breakfast that contained 0.625 mmol calcium. Before and 220 min after the bolus seru m strontium concentrations were determined by means of atomic absorpti on spectrophotometry (coefficient of variation: within day 4.8 %, n = 10; day-to-day 9.5 %, n = 8). The error of the method was 2.7 %. Calcu lation of the fractional strontium absorption rate considered the resp ective distribution volume (extracellular fluid; either estimated usin g body weight or determined by means of bioimpedance analysis [BIA]). Average absorption rates were 13.3 +/- 3.1 % and, considering BIA meas urement 13.6 +/- 2.6 %, respectively. Smoking, exercise and, use of or al contraceptives showed no effects. Our oral strontium test is charac terized by excellent reliability, easy handling and low costs and, thu s, is suitable for routine use.