Among clinical laboratory tests, urine testing has a particularly long history, and it continues to serve as an important screening test for kidney, urinary tract, and systemic diseases. Urine testing can accurately detect five abnormalities of urine, i.e., (1) pyuria, (2) bacteriuria, (3) hematuria, (4) proteinuria, and (5) metabolically abnormal urine (e.g., crystalluria, glycosuria). Urinary sediment examination is a morphological examination that accurately identifies and roughly counts urine formed elements, i.e., epithelial cells, blood cells, casts, salts/crystals, and bacteria, to provide information for detecting any pathological condition accompanying urine abnormalities in combination with qualitative urinary test findings. For urinary sediment examination procedures in Japan, the Japanese Committee for Clinical Laboratory Standards (JCCLS) proposed guidelines on urinary sediment examination procedures, namely GP1-P3 (urinary sediment examination procedures 2000), in 2000, and the revised version, named GP1-P4 (urinary sediment examination procedures 2010), was released in 2010. In this part, we outline the urinary sediment examination procedures according to GP1-P4 (with some modifications).
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