leukopenia
Meaning of leukopenia: Which type of white cell is missing matters more than the total, since neutrophils carry most of the protection against bacteria.
Definition of leukopenia
Leukopenia is a white blood cell count below the normal range for the laboratory reporting it. White cells are the immune system's front line against infection, so a shortage can leave the body slower to contain invading organisms. The term describes the total count only, and says nothing about which of the several white cell types has fallen or why.
How leukopenia is built
- leuk/o Combining form · Greek white
- -penia Suffix · Greek deficiency, abnormally low count
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
What makes the count fall?
| Mechanism | Usual causes |
|---|---|
| Too few produced | Chemotherapy and radiation, other drugs that suppress the marrow, severe deficiency of vitamin B12 or folate, leukemia or another cancer filling the bone marrow |
| Destroyed faster than replaced | Autoimmune disease such as lupus, an enlarged spleen trapping cells, occasional drug reactions |
| Consumed or shifted out of the circulation | Overwhelming infection using cells faster than they can be made, or cells moving from the flowing blood into tissue and vessel walls |
Ordinary viral infections are the commonest cause, and the dip is usually brief. What matters more than the number itself is the mechanism behind it, because that governs how far the count falls and how long it stays down. A drop during a viral illness lifts as the illness clears, while one caused by failing marrow does not.
Why does the differential matter more than the total?
White cells are not one population. Neutrophils deal with bacteria and fungi, lymphocytes handle viruses and direct the wider response, and monocytes, eosinophils and basophils each do something different again. A blood cell count reported with a differential shows which type has fallen. Neutrophils normally make up the largest share, so a low neutrophil count pulls the total down and carries almost all of the infection risk people associate with leukopenia. A fall confined to lymphocytes means something quite different, and can follow steroid treatment, a viral infection or a long standing illness without leaving anyone especially exposed to bacteria.
Is a low count always a problem?
Not necessarily. Reference ranges are drawn from populations, and healthy people sit outside them at both ends. A lower baseline neutrophil count is common and entirely benign in people of African, Middle Eastern and West Indian ancestry, reflecting an inherited difference in where neutrophils are held rather than any weakness of defense. Counts also swing with time of day, recent exercise and recent illness, so a single value slightly below the range in someone who feels well carries less weight than a trend across several samples.
Also known as
Used in a sentence
A complete blood count revealed leukopenia during the patient's follow-up visit after chemotherapy.
Good to know
Leukopenia is a broader finding than neutropenia, which refers specifically to a shortage of neutrophils, the white blood cell type responsible for most of the infection risk associated with a low count.
Word origin
Where “leukopenia” comes from
Formed from leuko-, Greek for white, and -penia, from penia, meaning poverty or deficiency.