Does a leukocytosis (elevated white blood cell count) of 11,000 cells per microliter warrant a workup in the absence of signs of infection?

From the Guidelines

A leukocytosis of 11,000 cells per microliter does not warrant a workup in the absence of signs of infection. This value is only slightly above the traditional upper limit of normal and falls within the normal range for many laboratories. According to the clinical practice guideline for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the infectious diseases society of america 1, a complete blood cell count should be performed for residents suspected of having infection, but the presence of an elevated WBC count is defined as 14,000 cells/mm³ or higher.

The guideline suggests that 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 due to the low potential yield 1. Many benign conditions can cause transient mild leukocytosis, including physical or emotional stress, exercise, pregnancy, smoking, certain medications, and even the normal diurnal variation in white blood cell counts.

Key points to consider:

• The patient's asymptomatic status without fever, localized pain, or other signs of infection
• The mild elevation of the white blood cell count, which is only slightly above the traditional upper limit of normal
• The potential for benign conditions to cause transient mild leukocytosis
• The low potential yield of additional diagnostic tests in the absence of specific clinical manifestations of infection

Given these considerations, observation with possible repeat testing at a later date is a reasonable approach. However, if the elevation persists on subsequent tests or increases significantly, or if the patient develops symptoms, further evaluation would be appropriate at that time.

From the Research

Leukocytosis Workup

• A leukocytosis of 11,000 cells per microliter may not necessarily warrant a workup in the absence of signs of infection, as it can be caused by various benign conditions such as physical or emotional stress, medications, or inflammatory processes 2, 3.
• However, it is essential to consider the patient's overall clinical presentation, medical history, and other laboratory results to determine the need for further evaluation 3.
• In some cases, leukocytosis can be a sign of a more serious underlying condition, such as a primary bone marrow disorder, which may require prompt attention and referral to a specialist 2, 3.

Differential Diagnosis

• The differential diagnosis for leukocytosis is broad and includes infections, inflammatory conditions, medications, and primary bone marrow disorders 2, 3.
• A thorough physical examination, medical history, and laboratory evaluation, including a complete blood count with differential and peripheral smear, can help identify the underlying cause of leukocytosis 3.

Clinical Context

• In the absence of signs of infection, a leukocytosis of 11,000 cells per microliter may be considered a relatively mild elevation, and further workup may not be necessary unless other clinical features suggest an underlying malignancy or other serious condition 2, 3.
• However, in certain clinical contexts, such as in critically ill patients or those with a history of recent surgery, leukocytosis may be a common finding and may not necessarily indicate an underlying infection 4, 5.
• In these cases, the clinical context and other laboratory results should be taken into account when determining the need for further evaluation or treatment 4, 5.