False macrocytosis in chronic lymphocytic leukemia and how we can correct it

Abstract

Aim: To present a case report of CLL, with a false macrocytosis caused by an important lymphocytosis and to demonstrate how we were able to detect it and our action to correct it. Methodology: When we have double population RBC histogram we have to use another parameter is the red blood cells most frequent volume (R-MFV) that defines the peak of the curve and fits the MCV in normal distribution. Results: CBC revealed leucocytosis (60×109/L), moderate normochromic anaemia (haemoglobin of 11.9 g/dL, MCV of 125 fl, In our case R-MFV is of 107 fl. The macrocytosis is still present; but would not be expected to reach 125 fl. It is also necessary to recalculate the parameters which depend on the MCV. Liver laboratory tests are abnormal in relation to the liver failure. This explains the mild macrocytosis observed even after correction of MCV. Conclusion: Pronounced leukocytosis can lead to overestimation of the MCV, especially in chronic lymphoid leukemia, therefore we must be careful when we interpret the parameters of complete blood count.