The Percentage of Pelgeroid Polymorphs (ppp) of Widell et al for neutrophils can be used to evaluate a patient with myelodysplasia. The ppp from the peripheral blood smear provides information that complements that provided by examination of the bone marrow. The authors are from Karolinska, Huddinge and Danderyd Hospitals in Stockholm.


Patient exclusion: A patient with congenital Pelger-Huet anomaly.


The ppp can be determined on either the bone marrow or the peripheral blood smear. The ppp for bone marrow and peripheral blood show a linear relationship, as shown in Figure 3 (Widell et al, page 118).


Pelgeroid nuclei:

(1) monolobated

(2) bilobated with straight connecting strand (dumbbell-shaped)

(3) bilobated with curved connecting strand (band-like)


The connecting strand in bilobated forms must be less than one third of the total width of the nucleus.


percent pelgeroid polymorphs =

= (number of neutrophils with a pelgeroid nucleus) / (number of neutrophils counted) * 100%



• The normal ppp is <= 5%.

• The higher the ppp the greater the degree of bone marrow dysplasia.

• A ppp >= 20% tends to be seen in patients with bi- or tri-lineage dysplasia in the bone marrow.


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