“Daisy-like” crystals: A rare and unknown type of urinary crystal

Advances in the identification of calcium carbonate urinary crystals

“…However, the relationship between urinary environment, concentration between different ions and the formation of calcite, aragonite and vaterite, cannot be still answered in this study. Moreover, our patient and all patients except one in the series reported by Fogazzi et al were females [10,11]. No clear explanation can be provided to explain the high prevalence of female gender and alkaline urine among patients who form vaterite in urine.…”

“…Flattened rectangles slightly birefringent under polarized light; 2. Non birefringent "daisy-like" crystals, identical to those described elsewhere [10,11]; 3. Strongly birefringent sticks and needles with welldefined edges (Figures 1 and 2).…”

“…Moreover, it has been reported that, in the thin descending limb of the Henle's loop, urine is supersaturated not only with calcium phosphate but also with Ca-carb [19]. The clinical meaning of Ca-carb crystals in the urine of humans is unclear at the moment, even though a possible association with a diet rich in vegetables has been hypothesized for some subjects whose urine contained daisy-like crystals [10,11].…”

Daisy-like crystals: Not just the result of sampling artifact and not only in urine

“…The same crystals were also found in two samples containing only hard water, again boiled and then cooled: one collected by the patient's family at laboratory request, the other collected under experimental conditions in the laboratory. These findings led the authors to hypothesize that DLcr previously described by us [2,3] and by Frochot and co-workers [4] could be the result of urine contamination due to urine collected in containers sterilized at home by using boiled water with a high limescale content.…”

“…In order to verify the hypothesis proposed by Hudák and co-workers, we have retraced the urine collection procedures used by the subjects described so far [2][3][4] by contacting the laboratory professionals who had found DLcr in their urine. The results, reported in Table 1, demonstrates that 9 out of 11 subjects had used appropriate sterile plastic containers (tubes or jars), either bought in pharmacy or supplied by laboratories, while for 2 other subjects no information could be retrieved (Table 1: patient 4 did not remember how she had collected the urine in October 2011; patient 8, a 93-year-old woman in 2016, could not be reached).…”