What is the role of blood tests in the workup of cold agglutinin disease?

Updated: Aug 28, 2018
  • Author: Salman Abdullah Aljubran, MD; Chief Editor: Michael A Kaliner, MD  more...
  • Print
Answer

Ensure proper handling of specimens when looking for cold agglutinins (ie, keeping the blood warm until it is tested). Blood specimens are commonly placed in a laboratory refrigerator until they are tested, but this practice must be avoided when testing for cold agglutinins. Blood studies used in the diagnosis of cold agglutinin disease include the following:

  • Complete blood cell count (CBC) with differential
  • Peripheral blood smear
  • Reticulocyte count
  • Direct Coombs test (direct antiglobulin test [DAT])
  • Serum protein electrophoresis and serum immunoelectrophoresis (immunofixation)
  • Cold agglutinin titer

Note that the direct Coombs test (direct antiglobulin test [DAT]) should be performed with samples at 35-37°C, using polyspecific and monospecific Coombs sera, including monospecific anti-C3 and IgG antisera.

Significant findings on other blood tests include the following:

  • Lactate dehydrogenase (LDH) and total and direct bilirubin values are elevated in cold agglutinin disease, depending on the extent of hemolysis.
  • The haptoglobin level may be reduced when hemolysis is active and ongoing with an intravascular spillover from a massive extravascular process and in the absence of significant liver disease.
  • Cryoglobulin levels should be tested only if vascular purpura or other atypical findings, such as elevated levels of IgM and/or hepatitis virus antibodies, are found. Again, proper handling of the sample, by keeping it warm until the test is run, is essential to avoid premature loss of the cryoglobulin

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!