Women have a "drumstick" arising from the nucleus of polymorphonuclear (PMN) leukocytes. It should not be referred to as "sex chromatin" since it was shown by Ashley in 1957 to be unrelated to the sex chromatin of somatic cells. Although genetic tests are now readily available for determining a person's gender, this examination can still be useful as an inexpensive screening test or in resource-poor areas.


Nuclear findings seen in leukocytes from women (or anyone with more than 1 X chromosome):

(1) drumsticks in neutrophils

(2) sessile nodules in neutrophils

(3) nuclear sex chromatin (Barr body) in lymphocytes and monocytes


Although a blood smear can be examined for nuclear sex chromatin (Barr body), artifacts occur and the examination requires a special stain. In addition, it may be difficult to distinguish from nuclear clumping in leukocytes.


Features of the drumstick:

(1) The bulbous end is dense and measures 1.5 microns in diameter.

(2) There is a thin nuclear filament connecting the end to the rest of the nucleus.

(3) There should only be 1 per PMN (the presence of more than 1 suggests artifact).


The sessile nodule has the bulbous end of the drumstick but is connected to the nucleus by a broad base.


Specimen: smear prepared from fresh capillary blood (oxalated blood may have more artifacts)


Number of PMNs to count when looking for drumsticks: 500 or more


percent of cells with nuclear drumsticks =

= (number of cells with drumsticks) / (number of polymorphonuclear leukocytes counted) * 100%



• Most women have from 1-7% PMNs with drumsticks.

• Occasionally a woman may show down to 0.2% (1 in 500) PMNs with drumsticks.

• A woman with Turner Syndrome (XO) would not show drumsticks unless an XO/XX mosaic.

• A normal male should not have any drumsticks.

• Rarely a man may show a drumstick. However, the quantitation of sex chromosomes is needed to determine if the person has more than 1 X chromosome (XXY, XXXY, etc.)

• Rarely a male fraternal twin with a female twin will show a small number of drumsticks.

• A phenotypic female without drumsticks may have testicular dysgenesis.


Differential diagnosis (artifacts confused with drumsticks):

(1) racquets (have a cleared or hypodense center)

(2) small nuclear clumps


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