Milliosmoles and osmolarity of a preparation
Ideal osmolarity (mOsm/L) of a solution of up to two solutes from concentration, molecular weight, and particles.
Inputs
2 of 3Solute 1
Optional
g/mol
Optional
Solute 2
Optional
Optional
g/mol
Optional
When to use
- Estimating whether a compounded solution is near isotonic.
- Checking a peripheral IV preparation.
Pearls and pitfalls
- This is the ideal (calculated) osmolarity; measured osmolality is usually lower because salts do not dissociate completely.
- Serum is about 285–295 mOsm/kg.
Why use
Adds the solutes with the arithmetic shown.
mOsm/L = Σ [concentration (g/L) ÷ MW (g/mol)] × particles × 1000