What is the purpose of the Gram stain in urinalysis?

The Gram stain is a crucial tool in urinalysis specifically for identifying the presence and type of bacteria in urine. Bacterial casts are formed when bacteria become trapped in the renal tubules and are excreted in the urine. These casts can indicate a kidney infection or pyelonephritis. The Gram stain helps to differentiate the types of bacteria present—whether they are Gram-positive or Gram-negative—which can provide insight into the infection’s potential causes and guide appropriate treatment.

While the other options (such as determining pH levels, analyzing glucose levels, and identifying crystals) are important aspects of urinalysis, they are not directly related to the role of the Gram stain. The Gram stain specifically focuses on bacterial identification, making it an essential procedure for diagnosing urinary tract infections and assessing the health of the urinary system.