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Osmolality measures solute concentration in body fluids. It's critical for diagnosing hyponatremia, hypernatremia, and fluid disorders.

सूत्र

Calculate: Osm = 2[Na] + (Glu/18) + (BUN/2.8)
Na
Na value — Variable used in the calculation
BUN
BUN value — Variable used in the calculation

चरण-दर-चरण मार्गदर्शिका

  1. 1Calculate: Osm = 2[Na] + (Glu/18) + (BUN/2.8)
  2. 2Normal: 280-310 mOsm/kg
  3. 3Compare measured to calculated osmolality

हल किए गए उदाहरण

इनपुट
Na 128, glucose 200, BUN 28
परिणाम
Osm ≈ 318 (high), measured lower suggests hyponatremia
Pseudohyponatremia likely

सामान्य गलतियां जिनसे बचना है

  • Neglecting glucose and BUN contributions in hyperglycemia/uremia
  • Confusing osmolality with osmolarity (different in concentrated solutions)

अक्सर पूछे जाने वाले प्रश्न

What's the osmolal gap?

Difference between measured and calculated osmolality. Large gap suggests unmeasured osmoles (ethanol, methanol, etc.).

How does osmolality relate to sodium?

Sodium is the main determinant of osmolality; hyponatremia usually means hypoosmolality and vice versa.

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