If you're like many people, you probably have an annual physical exam that includes tests such as a complete blood count, blood sugar, and cholesterol. And chances are that the results you focus on are the cholesterol and triglycerides—if they're elevated, your health care provider may tell you to make some dietary changes to get them back into the normal range.

Why Worry About Your White Blood Cell Count?

While there is no special reason to focus on your white blood count, it can be important. An elevated white blood count (WBC) has serious health implications, say medical experts, because it can signal a blood cancer like leukemia."Sometimes an abnormal white count can give hints of an underlying malignancy," says Andrew Yeager, MD, of the University of Arizona. When doctors look at the cells, he says, they also look at the types of white cells. "When it comes to white blood cells, it's definitely not one size fits all," Yeager explains.

Doctors look for immature white blood cells called blasts, which should never be in the bloodstream, he explains. "These blasts make more of themselves, and they begin to crowd out the normal cells when leukemia is present," Yaeger says. As more abnormal cells crowd out normal cells, a person's red blood cell count and platelet count can drop.

What Is a Normal White Blood Cell Count?

Normally, a person's white blood cell count is anywhere from 5,000 to 12,000, explains Michael Roth, MD, a pediatric hematologist at Montefiore Medical Center in New York City. "When the white blood cell count is elevated, it is most commonly a sign of infection or inflammation in the body," Roth says. "When the white blood cell count is extremely elevated, we worry more about leukemia."

However, an elevated white blood count does not necessarily mean a patient has leukemia, Roth says. Pneumonia and steroid medications can cause an elevated white blood count. And the count can go up for other reasons, so he says it's important to look at the whole picture.

What If An Elevated White Blood Cell Count Does Signal Leukemia?

Fortunately, treatment strides in leukemia mean that a patient's odds of survival are better than ever, though survival rates are tied to the type of leukemia and the age of the patient. The cure rate for childhood leukemia is very high, Yeager says. "The cure rate is not as high in adults," he says. "But thanks to chemotherapy and bone marrow transplants, the cure rate is encouraging."

So Should You Get Frequent Blood Tests To Check Your White Count?

No, says Roth. "If someone is getting sick with leukemia, that person will often see a primary care doctor with symptoms of worsening fatigue and fever," he says. "Getting routine checkups at your regular doctor is all that is needed."And, he says to keep in mind that leukemia is not all that common. "Pediatric cancers in general are exceedingly rare," Roth says. "Only a few thousand children are diagnosed with leukemia each year in the United States."

Michael Roth, MD, a pediatric hematologist at Montefiore Medical Center in New York City, reviewed this article.