From the Guidelines
A white blood cell (WBC) count of 11.5 thousand cells per microliter is slightly elevated but does not necessarily indicate a bacterial infection, as the threshold for concern is typically a WBC count of 14,000 cells/mm³ or higher, as suggested by 1. This mild elevation could be due to several factors including a minor infection, inflammation, stress, physical exertion, or even normal variation. Some key points to consider include:
- The presence of an elevated WBC count (WBC count, ≥ 14,000 cells/mm³) or a left shift (percentage of band neutrophils or metamyelocytes, ≥ 16%; or total band neutrophil count, ≥ 1500 cells/mm³) warrants a careful assessment for bacterial infection in any LTCF resident with suspected infection, with or without fever, as stated in 1.
- In the absence of fever, leukocytosis and/or left shift, or specific clinical manifestations of a focal infection, additional diagnostic tests may not be indicated, because of the low potential yield, as mentioned in 1.
- A complete blood cell (CBC) count, including peripheral WBC and differential cell counts, should be performed for all LTCF residents who are suspected of having infection within 12–24 h of onset of symptoms, as recommended by 1. No immediate treatment is required for this value alone. However, if you're experiencing symptoms like fever, fatigue, or pain, or if this is part of a pattern of persistently elevated WBC counts, you should consult with a healthcare provider. They may recommend additional tests such as a complete blood count with differential to determine which specific types of white blood cells are elevated, which can help identify the underlying cause, as suggested by 1. The elevation in WBCs occurs because your bone marrow produces more white blood cells in response to various triggers, as these cells are crucial components of your immune system that help fight infections and respond to inflammation.
From the Research
White Blood Cell Count of 11.5
- A white blood cell (WBC) count of 11.5 is considered elevated, as the normal range for WBC count is typically between 4,000 to 10,000 cells per microliter 2.
- According to a study published in the Southern Medical Journal, a WBC count between 11 and 14.5 × 10^9 WBCs/L may represent a normal value in hospitalized patients without infection, malignancy, or immune dysfunction 2.
- Elevated WBC counts have been associated with various conditions, including inflammation, infection, and immune system disorders 3, 4.
Association with Mortality and Morbidity
- A study published in the Circulation Journal found that elevated WBC counts were associated with an increased risk of all-cause and cardiovascular mortality 4.
- Another study published in the International Journal of Clinical Pharmacology and Therapeutics found that antibiotics can help prevent infection and reduce WBC counts and C-reactive protein levels in the perioperative period of cesarean section 5.
Genetic Associations
- A study published in Genes and Immunity used latent class mixed modeling to identify unobserved heterogeneity in longitudinal WBC count data and found genetic associations between WBC count trajectory phenotypes and regions on chromosomes 1p34.3 and 11q13.4 6.
- These genetic associations may provide insights into the underlying mechanisms of WBC count regulation and its relationship to various diseases 6.