Normal range: 4.5–8 (typically 5.5–6.5).

Clinical interpretation:

• Low (acidic) causes: High-protein diet, metabolic acidosis

• High (alkaline) causes: Urease-producing UTI, renal tubular acidosis

Stone correlation:

• Low pH: Uric acid, cystine

• High pH: Calcium phosphate, struvite

For healthy individuals: Primarily diet-driven unless persistent.