Albumin injection is a protein extracted from pooled human blood plasma. When injected intravenously as a 5% solution, increases the volume and osmotic pressure of plasma. The primary indication is treatment of hypovolemia, but it has some indications for severe edema secondary to kidney or liver disease. It had been used for a number of indications, such as increased intracranial pressure, where it has been shown to be of no benefit.
Since it is a natural blood product, it carries some risk of antigenicity and a low risk of infection; the supply also can be unpredictable. An alternative, Dextran 70, has no infection risk, but has its own problems of antigenicity. Hetastarch is considerably cheaper and has negligible risk of immune reaction. 
- Wong YY, Abramowitz PW, Mansur JM (January 1987), "(Abstract) Changing use patterns of plasma volume expanders through educational intervention.", Am J Hosp Pharm 44 (1): 102-5.