Diagnosis of Hematuria in the Urinary System Using Centrifuges

Hematuria is defined as the presence of blood (erythrocytes) in the urine. Most diseases affecting the urinary system can present with macroscopic (visible to the naked eye) or microscopic hematuria at some point in their evolution.

Although most of the time it has little clinical significance, on some occasions it can be the first indication of serious conditions, such as kidney diseases, urinary infections, urolithiasis (stones in the kidney or bladder), cancer of the urinary tract, among other disorders.

Detection Techniques for Red Blood Cells in Urine

Due to its clinical importance, various laboratory techniques have been developed to identify the presence of red blood cells in urine, with some of the most advanced being flow cytometry, counting chamber, or optical microscopy. 

However, despite advances in detection techniques, most clinical analysis laboratories continue to use, for their effectiveness and speed, two concatenated techniques: the use of dipsticks followed by a macroscopic examination of the urinary sediment.

Processes and Equipment

In more detail, dipsticks would be used as a screening method for urine received in the laboratory. Whenever the dipstick is positive for blood, the urine will subsequently be examined under a microscope. The standardized technique involves centrifuging 10 ml of urine at 1,500 rpm for 3-5 min in a round-bottom tube. For this process, our wide range of equipment can be utilized, depending on capacity needs, ranging from Microcen 24 to Unicen 21 or Consul 22, offering capacities that vary from 8 to 72 urine sample tubes, depending on the user’s capacity requirements. 

After centrifugation, the supernatant is discarded and the sediment is resuspended in 0.5-1 ml of the remaining urine. A drop of the resuspended sediment is observed under the microscope with a 400x objective, and the presence of pathology is determined according to established ranges.

Thus, the centrifugation of urinary sediment contributes to the diagnosis of these diseases, providing speed and reliability to what is the most commonly used technique for the detection of hematuria in clinical analysis laboratories.