Question 5.3

Give two causes for this appearance of the ultrafiltrate from a CVVHDF circuit.

[Click here to toggle visibility of the answers]

College Answer

Intravascular hemolysis
Rupture of filter membrane


Its difficult to find a reference for this. The appearance is clearly that of blood, or at least haemoglobin. How did this happen?

Well; its one of the following possibilities:

  • The filter membrane ruptured, releasing blood into the effluent
  • There is a massive intravascular haemolysis
  • The patient has recently received a dose of hydroxycobalamin, which tends to discolour all body fluids, and which will cause the blood detector in the dialysis machine to alarm.


Sutter, Mark, et al. "Hemodialysis complications of hydroxocobalamin: a case report." Journal of Medical Toxicology 6.2 (2010): 165-167.