Mage et al used a simple proportion to estimate 24-hour urine sodium excretion based on urine creatinine measurements.
Parameters:
(1) spot urine sodium concentration in mmol/L
(2) spot urine creatinine concentration in mg/dL
(3) estimated 24 hour urine creatinine excretion in mg/dL
estimated 24-hour urine sodium excretion in mg =
= 23 * (spot urine sodium) / ((spot creatinine) * 10) * (24 hour urine creatinine)
where:
• 23 is for conversion from mmol to mg for sodium.
• Multiplying by 10 converts mg/dL to mg/L
• The equations for estimating 24 hour urine creatinine excretion are referenced to Mage as well.
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Specialty: Nephrology, Clinical Laboratory
