[Ionic calcium in blood and urine. Methods of determination and methodological difficulties]

The present paper reports about the individual fractions of the plasma and urine calcium, further about the analytical methods for the determination of the ionic Ca, as well as about the methodical difficulties of the described analytical techniques. Considerations about the real informative value of the Ca2+ -determination in the urine led us to the conclusion that only the additional knowledge of the actual concentration of the stone-forming anions, the oxalate resp. the phosphate may mediate a more complete picture about the calculogenetic "aggressivity" of the urine under investigation.