Smudge cells seen on a peripheral blood smear are fragile cells that are damaged from the mechanical forces that occur as the smear is made. They usually represent variant lymphocytes or blasts. Their presence can cause a misleadinig differential count since they are not intact and so not included.


Patient selection: presence of multiple smudge cells



(1) Add 1 drop of serum albumin (often available in the blood bank) to 4 drops of the patient’s whole blood.

(2) Gently mix.

(3) Make a new blood smear trying to be as gentle as possible.

(4) Examine the new smear to see if the smudge cells are reduced. If not, repeat the process with two drops of albumin to 4 drops of the patient’s blood.

(5) Report the differential count, adding a note that it is done on an albumin smear.



• Red cell morphology is altered by the addition of albumin and should be evaluated on a smear without added albumin.


On alternative method might be to exam blood in a chamber with an alternative light source, thereby avoiding the actual making of a smear.


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