How does cold agglutinin affect MCHC?

If the cold agglutinin is operative at room temperature, then a falsely high mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) with a low RBC count are obtained due to agglutination of RBCs in the cold automated counter.

Does hemolysis increase MCHC?

Hemoglobin makes up approximately 33% of the volume of the cell. Erythrocytes cannot carry more hemoglobin in their cytoplasm than normal, so they cannot be hyperchromic. An increased MCHC is usually associated with hemolysis, either a result of disease or of improper venipuncture or sample handling.

Why is MCHC high in hemolytic anemia?

You’ll have a high MCHC value if there’s an increased concentration of hemoglobin inside of your red blood cells. Additionally, conditions where hemoglobin is present outside of red blood cells due to red blood cell destruction or fragility can produce a high MCHC value.

Does cold agglutinin disease cause hemolysis?

Cold agglutinins – Cold agglutinins are antibodies that recognize antigens on red blood cells (RBCs) at temperatures below normal core body temperature. They can cause agglutination of the RBCs (picture 1) and extravascular hemolysis, resulting in anemia, typically without hemoglobinuria.

How is hemolysis related to an elevated MCHC?

Hemolysis can interfere with the MCHC by falsely decreasing the HCT due to RBC destruction and potentially increasing measured Hb values, though I haven’t witnessed this. It may require rather severe hemolysis to be enough to trigger a further look into the MCHC. If the cause is in-vitro it may be best to re-collect.

Can a high MCV be an indication of a cold agglutinin?

There may also be an indication of cold agglutinins in the blood bank history. Often it is pretty apparent that you are looking at a cold agglutinin when you run the CBC and you get a shockingly high MCV and the analyzer flags all the RBC parameters.

What are the signs of cold agglutinin hemolytic anemia?

When this happens, there can be signs of intravascular hemolysis, including elevations of serum-free hemoglobin and hemoglobin in the urine. Patients with cold agglutinin disease have high levels of complement on the red cell membrane and, as a consequence, the standard therapies that are used for warm-mediated hemolysis fail.

How does cold agglutinin affect red blood cells?

There have been reports of anti-Pr cold agglutinins. 3 The resulting positive direct antiglobulin testing will interfere with red cell cross-matching, making transfusional support through the post-infectious interval challenging.

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