White blood cell count not a definitive indicator

I am writing to correct a misleading statement in the Feb. 3 article about the malpractice trial of Rob Small versus Dr. Patricia Duletsky.

The article concludes erroneously stating that an elevated white blood count (WBC) is an indicator of a bacterial infection. I do not know Dr. Duletsky and have no opinion on the malpractice case, but this statement is wrong and misleading.

First, women have an elevated WBC up to two-and-a-half times normal during most pregnancies.

Second, the WBC has neither the sensitivity nor the specificity to indicate a bacterial infection.

A test has 100 percent sensitivity when a negative result rules out the diagnosis, and a test has 100 percent specificity when a positive result rules in the diagnosis.

The WBC falls on both counts. In actual practice, patients with a low WBC during a severe illness are often sicker; their bodies are unable to mount the needed response to fight off infection.

Your readers need to know that an elevated white blood cell count neither rules in nor rules out a bacterial infection.