When to use albumin 5% (five percent human albumin) versus albumin 25% (twenty-five percent human albumin) in patients with hypovolemia (low blood volume)?

When to Use Albumin 5% vs 25%

Use albumin 5% for volume resuscitation in hypovolemic states, and reserve albumin 25% for situations requiring fluid mobilization or when volume restriction is necessary, such as in cirrhosis with ascites or when correcting severe hypoalbuminemia with concurrent fluid overload.

Key Physiologic Principles

The choice between albumin concentrations depends on your clinical goal:

• Albumin 5% (iso-oncotic) is primarily used to maintain intravascular volume in patients with hypovolemia, functioning similarly to crystalloids but with longer intravascular retention 1
• Albumin 25% (hyperoncotic) is used to mobilize extravascular fluid back into the vascular space or when volume restriction is needed 1

Both concentrations deliver the same amount of albumin per gram, but the volume effect differs significantly. Research demonstrates that 50 grams of albumin produces approximately 500 ml plasma volume expansion (11 ml/g of retained albumin) regardless of whether given as 5%, 20%, or 25% solution 2. The expansion depends on the amount of albumin given and the plasma volume deficit, not the concentration 2.

Clinical Scenarios for Albumin 5%

Use 5% albumin when volume expansion is your primary goal:

• Septic shock with hypotension in cirrhosis patients: 5% albumin demonstrated higher reversal of hypotension with improved 1-week survival (43.5% vs 38.3%, p=0.03) compared to normal saline 1
• General hypovolemic shock resuscitation: 5% albumin requires 2-4 times less volume than crystalloids to achieve similar hemodynamic endpoints and results in significantly lower pulmonary edema rates (22% vs 87.5% with saline) 3
• When large volumes are needed: 5% albumin is easier to infuse due to lower viscosity and contains balanced electrolytes 2

Clinical Scenarios for Albumin 25%

Use 25% albumin when you need oncotic pull or must restrict volume:

• Large-volume paracentesis in cirrhosis: Give 8 grams of albumin per liter of ascitic fluid removed (typically using 25% solution for practical volume considerations) 1, 4
• Spontaneous bacterial peritonitis: Administer 1.5 g/kg on day 1 and 1.0 g/kg on day 3 using concentrated albumin 1, 4
• Hepatorenal syndrome-AKI: Give 1 g/kg on day 1, then 20-40 g daily with vasoactive agents 4
• Severe hyponatremia in cirrhosis (<120 mEq/L): Hyperoncotic albumin helps mobilize extravascular fluid while correcting hypoalbuminemia 1
• Intradialytic hypotension with hypoalbuminemia: 20-25% albumin reduces hypotension and improves fluid removal better than saline when serum albumin is low 5

Important Caveats and Pitfalls

Avoid these common errors:

• Don't use albumin to simply "correct" low albumin levels in critically ill patients without specific indications—this does not improve outcomes and increases pulmonary edema risk 1
• Beware of fluid overload with 25% albumin: The ATTIRE trial showed that targeting albumin >30 g/L in hospitalized cirrhosis patients significantly increased pulmonary edema and fluid overload without improving outcomes 1
• Monitor closely when using 25% albumin: Hyperoncotic solutions can cause rapid intravascular volume expansion, potentially precipitating pulmonary edema in patients with cardiac dysfunction 1
• Hypoalbuminemia moderates albumin effectiveness: The volume effect of albumin is greater when baseline serum albumin is ≤25 g/L, requiring less crystalloid co-administration 5

Practical Algorithm

For hypovolemic shock:

1. Start with 5% albumin at 250 ml boluses every 15 minutes until hemodynamic targets achieved 3
2. Expect to use 2-4 times less volume than crystalloids 3
3. Monitor for pulmonary edema (though risk is lower than with crystalloids) 3

For cirrhosis complications:

1. Large-volume paracentesis (>5L): Use 25% albumin at 8 g/L removed 1, 4
2. SBP: Use 25% albumin at 1.5 g/kg day 1.0 g/kg day 3 1, 4
3. Septic shock: Use 5% albumin for volume resuscitation 1

For severe hypoalbuminemia with volume overload:

1. Use 25% albumin to mobilize fluid while minimizing additional volume 1
2. Combine with diuretics only in specific cirrhosis scenarios 1