Iodine (¹²⁵I) human albumin (trade name Jeanatope) is human serum albumin iodinated with iodine-125, typically injected to aid in the determination of total blood and plasma volume.^[1][2]

Iodine-131 iodinated albumin (trade name Volumex) is used for the same purposes.^[3]

Medical uses

Iodine (¹²⁵I) human albumin is used to determine a person's blood volume. For this purpose, a defined amount of radioactivity in form of this drug is injected into a vein, and blood samples are drawn from a different body location after five and fifteen minutes. From the radioactivity of these samples, the original radioactivity per blood volume can be calculated; and knowing the total amount of radioactivity injected, one can calculate the total blood volume.^[1]

It can also be used to calculate the blood plasma volume using a similar method. The main difference is that the drawn blood sample has to be centrifuged to separate the plasma from the blood cells.^[1]

Contraindications

The US Food and Drug Administration lists no contraindications for this drug.^[1]

Adverse effects

There is a theoretical possibility of allergic reactions after repeated use of this medication.^[1]

Pharmacokinetics

Iodine-125 is a radioactive isotope of iodine that decays by electron capture with a physical half-life of 60.14 days. The biological half-life in normal individuals for iodine (¹²⁵I) human albumin has been reported to be approximately 14 days. Its radioactivity is excreted almost exclusively via the kidneys.^[1]

References