The information in this article is for educational purposes only and does not replace medical advice. In case of doubts or symptoms, always consult a healthcare professional

Urinalysis is a routine test that provides valuable insights into overall health. It is a simple yet effective test for detecting issues such as urinary tract infections, diabetes, liver or kidney diseases. It is often performed as a baseline check or when specific symptoms are present.

How is it performed and when should you get tested?

The first-morning urine sample (first void urine) is ideal because it is more concentrated and representative. To ensure reliable results, the analysis should be performed within two hours of collection.

Urinalysis consists of three main components:

1. Physical examination – Evaluates urine appearance (color, clarity, odor, and specific gravity).
   
2. Chemical analysis – Uses reagent strips (dipsticks) to detect abnormal substances.
   
3. Microscopic examination – Identifies cells, crystals, and microorganisms.

Physical examination: color, clarity, and specific gravity

• Color can range from pale yellow to dark yellow depending on hydration levels. Dark urine may indicate dehydration or liver problems.
  
• Clarity is typically clear; cloudy urine may suggest issues such as infections, metabolic diseases, or the presence of crystals.
• Urine specific gravity (USG) indicates the kidney’s ability to concentrate urine. Low specific gravity (hyposthenuria) means the urine is very diluted, while high specific gravity (hypersthenuria) indicates more concentrated urine. A consistently low specific gravity similar to that of plasma (isosthenuria) can signal kidney problems (loss of the ability to concentrate or dilute urine).

Chemical analysis: what to look for?

Reagent strips detect substances that are usually absent in urine:

• Urine pH: Normally slightly acidic (5.5–6.5). A significantly higher or lower pH may indicate infections or metabolic disorders.
  
• Proteinuria (protein in urine): Proteins are usually absent or found in minimal amounts. Excessive protein may indicate kidney disease.
  
• Glycosuria (glucose in urine): Normally absent; its presence may be a sign of uncontrolled diabetes.
  
• Bilirubin and urobilinogen: Their presence may suggest liver disease or bile duct obstruction.
  
• Ketones: Detected in urine during prolonged fasting, low-carbohydrate diets, or uncontrolled diabetes.
  
• Red blood cells (RBCs) and hemoglobin: Hematuria (blood in urine) may result from infections, kidney stones, or other conditions.
  
• White blood cells (WBCs) and leukocyte esterase: Elevated levels may indicate urinary tract inflammation or infection.
  
• Nitrites: Suggest the presence of bacteria that cause urinary tract infections.

Microscopic examination: what can be found?

Centrifuged urine is analyzed for specific elements:

• Urinary casts: Cylindrical structures formed in the kidney tubules, hence the name. They may be composed of proteins (hyaline casts), white blood cells, red blood cells, or epithelial cells. Certain types, such as red blood cell casts, are associated with conditions like glomerulonephritis.
• Urinary crystals: Some are commonly found in healthy individuals, while others may suggest kidney stones or metabolic disorders.
• Epithelial cells: Normally found in small amounts; an increase may suggest infections or inflammation.
• Blood cells: Microscopic examination can reveal red blood cells (erythrocytes) and white blood cells (leukocytes). An increased number of erythrocytes may indicate hematuria, while a higher number of leukocytes can suggest a urinary tract infection.
• Bacteria and microorganisms: Their presence confirms a urinary tract infection.

When should you be concerned?

Some results may require further medical evaluation:

• Blood in urine without an obvious cause (e.g., menstruation or intense physical activity).
• Glucose in urine without a known diagnosis of diabetes.
• Persistent protein in urine, which may indicate kidney disease.
• Significantly altered pH, potentially linked to metabolic disorders or infections.

Beyond basic urinalysis, urine can also be used for important screening tests in clinical practice:

Albumin-to-creatinine ratio (ACR): Measures protein loss in urine, especially albumin. It is an early indicator of kidney damage and is used to screen for chronic kidney disease.

Urinary tract infections: The combination of leukocytes (leukocyte esterase) and nitrites in chemical tests can suggest the presence of pathogenic bacteria in the urine—even in asymptomatic cases.

Urinalysis is a simple but highly valuable test for detecting early signs of disease. If results show abnormal values, it is important to consult a doctor for further evaluation.