What is the expected pH range of a freshly voided urine specimen?

What is the expected pH range of a freshly voided urine specimen?

• A. 3.5-8.0
• B. 3.5-9.0
• C. 4.0-8.5
• D. 4.5-8.0

Answer: (D)

Freshly voided urine has a broad but defined range for pH because urine reflects the balance of acids and bases the kidneys excrete and is influenced by diet and metabolism. The commonly accepted reference interval for a fresh specimen is about 4.5 to 8.0, which captures the usual physiologic variation in healthy individuals. Very acidic urine (below ~4.5) or very alkaline urine (above ~8.0) is uncommon in a normal, freshly collected sample. Remember that pH can shift if the urine sits at room temperature, as bacteria convert urea to ammonia and raise the pH, so testing promptly or refrigerating the sample helps preserve accuracy.

Freshly voided urine has a broad but defined range for pH because urine reflects the balance of acids and bases the kidneys excrete and is influenced by diet and metabolism. The commonly accepted reference interval for a fresh specimen is about 4.5 to 8.0, which captures the usual physiologic variation in healthy individuals. Very acidic urine (below ~4.5) or very alkaline urine (above ~8.0) is uncommon in a normal, freshly collected sample. Remember that pH can shift if the urine sits at room temperature, as bacteria convert urea to ammonia and raise the pH, so testing promptly or refrigerating the sample helps preserve accuracy.