Polarized light micrograph of creatinine crystals, the end product of creatine phosphate, a molecule of major importance for energy production in muscle tissue. Creatinine is removed or cleared from the blood plasma mainly by glomerular filtration, and is excreted in the urine. Creatinine levels in blood and urine may be used to calculate the creatinine clearance rate, which correlates with the glomerular filtration rate, and is therefore an indicator of kidney function. If renal filtration is deficient, creatinine blood levels rise. A low or decreased creatinine clearance level may indicate such conditions as glomerulonephritis, ureteral obstruction, or pyelonephritis (kidney infection), and may be associated with an increased risk for the development of diabetes mellitus type 2 and prostate cancer. Field of view size: 0.74 x 1.11 mm (0.029 x 0.044 in)