What is the significance of the 24-hour urine potassium to creatinine ratio?

From the Research

Significance of the 24-hour Urine Potassium to Creatinine Ratio

The 24-hour urine potassium to creatinine ratio is a significant marker for evaluating renal potassium losses and progression of chronic kidney disease (CKD) 1, 2, 3.

• The ratio can indicate increased 24-hour urinary potassium excretion and may be a useful screening test when a reliable 24-hour urine collection is not available 1.
• A low urinary potassium-to-creatinine ratio is associated with a higher risk of CKD progression 3.
• The ratio can be used to estimate 24-hour urinary potassium excretion with reasonable clinical accuracy using the PAHO formula 1.

Relationship with Kidney Function

The 24-hour urine potassium to creatinine ratio is related to kidney function decline in patients with CKD 4, 3, 5.

• Kidney function decline is associated with urinary sodium and potassium excretion, with opposite associations between glomerular filtration rate (GFR) decline and urinary excretion rates of sodium and potassium 4.
• Low urinary potassium excretion is associated with progression of CKD, and the relationship between creatinine clearance and fractional excretion of potassium differs between old and chronic renal disease groups 3, 5.

Diagnostic Value

The 24-hour urine potassium to creatinine ratio has diagnostic value in evaluating hypokalemia and renal potassium losses 2.

• The ratio can indicate renal potassium losses with a sensitivity of 96% and specificity of 72.7% compared to 24-hour urinary potassium excretion 2.
• The ratio can be used as a marker for renal potassium losses, especially in patients with normalized serum potassium levels during treatment 2.