Which statement correctly describes correcting serum sodium in DKA?

Which statement correctly describes correcting serum sodium in DKA?

• A. Subtract 2 for every 100 mg/dL glucose above 100
• B. Add 1.6 to sodium for every 100 mg/dL glucose above 100
• C. Do not adjust sodium for glucose
• D. Multiply sodium by 1.1

Answer: (B)

In hyperglycemia, the high glucose draws water from inside cells into the extracellular space, diluting the serum sodium. To estimate the true sodium level in DKA, you adjust by adding about 1.6 mEq/L of sodium for each 100 mg/dL increase in glucose above 100 mg/dL. So, corrected sodium = measured Na + 1.6 × [(glucose − 100) / 100]. For example, if glucose is 350 mg/dL, that's 250 above 100; 250/100 = 2.5 increments; 2.5 × 1.6 ≈ 4.0 mEq/L added to the measured sodium. This corrected value guides fluid and insulin decisions, since as glucose falls during treatment, the sodium will rise, and you don’t want to overcorrect too quickly. The other approaches aren’t used: subtracting 2 per 100 would invert the effect; not adjusting ignores the osmotic water shift; multiplying by 1.1 isn’t a recognized correction method.

In hyperglycemia, the high glucose draws water from inside cells into the extracellular space, diluting the serum sodium. To estimate the true sodium level in DKA, you adjust by adding about 1.6 mEq/L of sodium for each 100 mg/dL increase in glucose above 100 mg/dL. So, corrected sodium = measured Na + 1.6 × [(glucose − 100) / 100].

For example, if glucose is 350 mg/dL, that's 250 above 100; 250/100 = 2.5 increments; 2.5 × 1.6 ≈ 4.0 mEq/L added to the measured sodium. This corrected value guides fluid and insulin decisions, since as glucose falls during treatment, the sodium will rise, and you don’t want to overcorrect too quickly.

The other approaches aren’t used: subtracting 2 per 100 would invert the effect; not adjusting ignores the osmotic water shift; multiplying by 1.1 isn’t a recognized correction method.