Equine Calculated Osmolality (SI) Explained

Learn the formula, clinical use and limitations of the equine calculated osmolality (si).

Calculates estimated serum osmolality using SI-unit sodium, glucose and urea concentrations.

Formula

value = 2*sodium + glucose + urea

What this calculator does

Calculates estimated serum osmolality using SI-unit sodium, glucose and urea concentrations.

Clinical use

Calculated osmolality is an estimate. Compare with measured osmolality when an osmolal gap is clinically important.

Important limitations

Unit errors involving glucose, urea or BUN can create large calculation errors.

References

  1. Hughes D et al. Harmonising reference intervals for calculated serum osmolality, anion gap and albumin-adjusted calcium.

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