Thoughts on a Lower Optimal Range for Total WBCs

Elevated WBCs are associated with infection, inflammation, and several chronic diseases. Low WBCs point towards a potential immune insufficiency. We have thoroughly reviewed the literature and revised the ODX Range for WBC - Total. 

A study out of Taiwan, using data from a health check program, found a significant association between increasing white blood cell (WBC) counts and C-reactive protein as well as neutrophil and monocyte percentage, suggesting that higher WBCs are associated with increased inflammation which is widely accepted. Researchers also point out that increased WBCs are associated with non-infectious conditions, including hypertension, cardiovascular morbidity, obesity, hypertriglyceridemia, lower HDL, hyperinsulinemia, and smoking. The study found that the mean WBC for those with the lowest CRP value of less than 1 mg/L was associated with a mean WBC of 5.97 k/cumm. 

Huang et al. noted additional research confirming an increased risk of cardiovascular disease with WBCs above 8.1 compared to below 6.6 in Caucasian males and increased risk in African Americans with WBC above 7.0 compared to below 4.8.

In the 44-year Baltimore Longitudinal Study of Aging, researchers concluded that those with a WBC below 3.5, or above 6.0, had a significantly greater mortality risk than those with WBCs within a range of 3.5-6 (Ruggiero 2007):

• A WBC count of 6-10 was associated with a 30-40% greater risk of mortality
• WBCs below 3.5 was associated with a 3-fold increase in mortality
• WBCs above 10 were associated with 2-fold increased mortality compared to a WBC count of 3.5-6.
• Those participants who died were more apt to smoke, be less physically active, and have a worse cardiovascular health profile than survivors.

Further evaluation of the predictive value of the complete blood count in assessing cardiovascular risk confirmed that cardiac patients with a WBC count of 6 or below had the lowest mortality. Lower values for hematocrit, MCV, MCHC, RDW, and platelets were also associated with a reduced risk of mortality (Anderson 2007).

The revised ODX Range for WBC- Total is 3.8 - 6.0 k/cumm.

References

Anderson, Jeffrey L et al. “Usefulness of a complete blood count-derived risk score to predict incident mortality in patients with suspected cardiovascular disease.” The American journal of cardiology vol. 99,2 (2007): 169-74. doi:10.1016/j.amjcard.2006.08.015

Huang, Zei-Shung et al. “Revision in reference ranges of peripheral total leukocyte count and differential leukocyte percentages based on a normal serum C-reactive protein level.” Journal of the Formosan Medical Association = Taiwan yi zhi vol. 106,8 (2007): 608-16. doi:10.1016/S0929-6646(08)60017-0

Ruggiero, Carmelinda et al. “White blood cell count and mortality in the Baltimore Longitudinal Study of Aging.” Journal of the American College of Cardiology vol. 49,18 (2007): 1841-50. doi:10.1016/j.jacc.2007.01.076