Artifacts/ contaminations

Artifacts and contaminations are elements observed in the sediment that are due to incorrect sample collection or preservation.

Fibers and threads

Fibers and threads from clothing material can be found in the urine.

Starch corns

Starch corns are present in almost all powders and can be found in the urine as colorless to light brown amorphous crystals. These crystals are spherical and highly birefringent. They are colored in red with iodine. They appear as "pseudo-maltese crosses" in polarized light. Their brefringent pattern is different from lipid crystals.

Starch corn Bright field microscope	"Pseudo-maltese cross " Polarized light	Real maltese cross Polarized light

Feces

Contamination with feces occurs particularly in samples from pediatric or geriatric and demented patients.

Other artifacts and contaminations

Hair, pollen grains and worm eggs can also be observed in the urine.