[Modified rapid test for the semiquantitative determination of cystine in the urine].

The present study describes a modified method of the semiquantitative determination of cystine in the urine which is based on the decomposition of cystine by dithionite ions and formation of a mixed nickel/cystein/sulfide-complex. The method is suitable as rapid and search test, it guarantees an acceptable reproducibility as well as the exactness of the values and is simply to be performed in every clinical-chemical laboratory. The criteria of analytic applicability are confirmed in comparisons of methods. It must be urged to treat fresh urines.