There are three types of routine urine tests in our hospital: 1) simple routine urine; 2) routine urine + sediment; 3) routine urine + microscopy. There is no red blood cell count in routine urine, only urine occult blood. Urine sediment: Our hospital (Pediatrics Building) uses the instrument U-F1001 to do the count with a flow cytometer, which is done automatically by the machine; urine microscopy Our hospital (Laboratory Department, 3rd floor) uses the instrument CK500 to do the count of cells with the human eye. If there are tens of grids, first roughly see if uniform, and then count several grids to take the average. If the volume of the grid is 0.01uL, count 5 grids a total of 15, can be derived from the results of 300 / uL. First let’s understand the principle of urine occult blood test: If there are red blood cells in the urine, there is a kind of hemoglobin in the red blood cells for ferrous hemoglobin, which has weak peroxidase activity, can make the oxides in the urine test paper (such as peroxyanisole) to release new ecological oxygen, and oxygen can oxidize the test paper with o-toluidine to blue. The instrument then determines whether or how positive the urine occult blood is based on the shade of this coloring, and thus presumes that red blood cells may be present in the urine. The use of urine occult blood testing to determine the presence of hematuria is mainly intended to be convenient and quick, and is suitable for outpatient screening of hematuria. If vitamin C is used clinically, it will be excreted from the urine in large amounts, which neutralizes the oxides in the urine test paper and cannot produce oxygen, causing a false negative reaction. And when the urinary tract infection, certain bacteria can produce peroxidase, causing a false positive; some crystals can also affect the determination of occult blood, causing a false positive result; some trauma or tissue infection will make the urine contains myoglobin will also make the urine occult blood is positive. In addition, urine occult blood test is also subject to some external factors such as whether the specimen is fresh, whether the reaction time is appropriate, whether the test strip is expired or contaminated, etc., which can cause false positive or false negative results of urine occult blood test. However, whether there are really red blood cells in the urine mainly relies on the retention of urine, centrifugation to take the sediment with microscopic observation to determine. Therefore, urine occult blood is not necessarily hematuria. When a positive urine occult blood is found, a urine sediment or urine microscopy must be performed to see a positive red blood cell count before it is determined to be hematuria.