Sodium Change Calculator in Hypertriglyceridemia

Estimate how much severe hypertriglyceridemia lowers a lab-measured serum sodium reading, and calculate the corrected (true) sodium using the standard volume-displacement formula.

Quick Facts

Correction factor
0.002 mEq/L per mg/dL triglycerides
Roughly a 2 mEq/L drop in measured sodium per 1,000 mg/dL rise in triglycerides.
When it matters
Usually above ~1,500-2,000 mg/dL
Clinically meaningful sodium displacement is uncommon at lower triglyceride levels.
Affected method
Indirect ion-selective electrode
Direct ISE and osmometry are largely unaffected by this artifact.

Your Results

Calculated
Sodium change (delta Na)
-
Estimated suppression from triglycerides
Corrected serum sodium
-
Measured Na + delta Na
Triglycerides used
-
Converted to mg/dL for the formula
Hyponatremia status
-
Based on the corrected sodium

Ready

Enter the measured sodium and triglyceride level, then calculate the correction.

About the Sodium Change Calculator in Hypertriglyceridemia

Severe hypertriglyceridemia can make a lab-reported serum sodium look falsely low, a phenomenon called pseudohyponatremia. Most hospital chemistry analyzers measure sodium indirectly: they dilute a sample of whole plasma and then measure the sodium concentration in that diluted mixture, assuming plasma is about 93% water. When triglycerides are very high, lipid takes up a larger share of the plasma volume, so the same sodium content is dissolved in less water than the analyzer assumes. The instrument reports a lower sodium than the true concentration in the plasma water, even though the patient's actual tonicity and total body sodium have not changed.

The correction formula

  • Estimated sodium change: delta Na (mEq/L) = 0.002 x triglycerides (mg/dL).
  • Corrected sodium: measured Na (mEq/L) + delta Na.
  • To convert triglycerides from mmol/L to mg/dL, multiply by 88.5 (this calculator does that conversion automatically when you select mmol/L).

Putting the result in context

This factor approximates the relationship described by Weisberg (1989), where roughly each 1,000 mg/dL rise in triglycerides was associated with about a 1.6 to 2 mEq/L fall in measured sodium. If the corrected sodium lands in the normal range (about 135 to 145 mEq/L), the original low reading is largely explained by the triglyceride artifact rather than true hyponatremia. If the corrected value is still below normal, true hyponatremia may be present alongside the lab artifact, and it deserves its own workup.

When to consult a professional

This tool performs the correction arithmetic only; it does not diagnose or direct treatment. A lab that suspects this artifact can often confirm it by re-measuring sodium with a direct ion-selective electrode or by measuring plasma osmolality, and any treatment decision for hyponatremia or hypertriglyceridemia should be made by the ordering clinician with the full clinical picture in view.

Frequently Asked Questions

What causes pseudohyponatremia in hypertriglyceridemia?
Standard lab sodium tests that use indirect ion-selective electrodes measure sodium concentration in a diluted sample of whole plasma, which is normally about 93% water. Severe hypertriglyceridemia replaces part of that plasma volume with lipid, so the same amount of sodium is dissolved in less of the sampled water. The result is a measured sodium that reads lower than the true concentration in the plasma water, even though total body sodium and tonicity are unchanged.
What formula does this calculator use?
It applies the standard volume-displacement correction: change in sodium (mEq/L) equals 0.002 times triglycerides in mg/dL. Corrected sodium equals measured sodium plus that change. This approximates roughly a 2 mEq/L drop in measured sodium for every 1,000 mg/dL of triglycerides, consistent with the relationship described by Weisberg (1989) and used in clinical chemistry references for triglyceride-related pseudohyponatremia.
Does correcting the sodium value change how it should be treated?
If the corrected sodium falls in the normal range, the low measured value is a lab artifact rather than true hyponatremia, so hyponatremia-specific treatment such as fluid restriction or hypertonic saline is unlikely to be appropriate; the underlying hypertriglyceridemia is the actual problem to address. If the corrected sodium is still low, true hyponatremia may coexist. Either way, this calculator performs the arithmetic only - treatment decisions belong to the ordering clinician, who can confirm the result with a direct ion-selective electrode or osmometry if needed.

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