With extensive analytical and clinical examinations it is shown that the proof of carbonate in apatite may allow no additional reference of an infection with urea-splitting bacteria. With certain analytical methods the presence of carbonate is demonstrable in each urinary calculus apatite phase. Carbonate-bearing apatite indeed is accompanied frequently with struvite, but may be occur also without an infection. Therefore, in the future it should be renounced on the differentiation of apatite and carbonate apatite in routine analyses of urinary calculi.