From the Guidelines
A persistently low white blood cell count (leukopenia) requires a comprehensive medical workup, including a thorough history and physical examination, CBC with differential and reticulocyte counts, and evaluation for infectious causes, as recommended by the American Society of Clinical Oncology clinical practice guideline 1. The workup should prioritize identifying potential causes of leukopenia, such as:
- Medications that may cause bone marrow suppression
- Exposure to radiation or toxins
- Recent viral infections
- Nutritional deficiencies, including vitamin B12 and folate deficiency
- Autoimmune disorders
- Primary bone marrow disorders, infiltrative diseases, or malignancies Further testing may include:
- Peripheral blood smear examination
- Inflammatory markers such as ESR and CRP
- Autoimmune screening with ANA, RF, and specific antibodies
- Bone marrow aspiration and biopsy
- Specialized testing, including flow cytometry, cytogenetics, and molecular studies
- Infectious disease workup, including HIV testing, hepatitis panel, EBV, CMV, and tuberculosis screening The most recent and highest quality study, published in the Journal of Clinical Oncology in 2018, recommends a similar approach to the diagnostic workup of leukopenia 1. Key components of the workup include:
- History and physical examination
- CBC, smear, reticulocyte count
- Viral studies, including CMV, HHV6, EBV, parvovirus
- Nutritional assessments, including B12, folate, iron, copper, ceruloplasmin, vitamin D
- Serum LDH, renal function
- Work-up for infectious causes
- Identify marrow hypo/aplasia
- Bone marrow biopsy and aspirate analysis
- Peripheral blood analysis, including neutrophil count, proportion of GPI-negative cells by flow for PNH
- Flow cytometry to evaluate loss of GPI-anchored proteins
- Type and screen patient for transfusions and notify blood bank that all transfusions need to be irradiated and filtered.
From the Research
Medical Workup for Persistently Low WBC
- A persistently low White Blood Cell (WBC) count, also known as leukopenia, can be a cause for concern and may require a thorough medical workup to determine the underlying cause 2.
- The complete blood count (CBC) is a crucial laboratory test in evaluating leukopenia, and it is essential to understand the components of the CBC, including the WBC count and differential 3, 4.
- A low WBC count can be associated with various conditions, such as infections, autoimmune disorders, and bone marrow disorders 2.
- The laboratory evaluation of leukopenia should be guided by the patient's clinical history and presentation, and the laboratorian's approach to consult cases should provide key laboratory-based insights to assist in resolving result discrepancies 3.
- In some cases, a low WBC count may be a sign of an underlying infection, such as tuberculosis, and further testing, such as sputum culture and analysis of WBC counts, may be necessary to determine the cause of the low WBC count 5.
- Point-of-care testing for WBC counting can be a useful tool in resource-limited areas, and microfluidic technologies have shown promise in achieving accurate and efficient WBC counting 6.
Diagnostic Approach
- The diagnostic approach to a persistently low WBC count should include a thorough medical history, physical examination, and laboratory tests, such as a CBC and differential count 2, 4.
- The patient's clinical presentation and medical history should guide the selection of additional laboratory tests and imaging studies to determine the underlying cause of the low WBC count.
- In some cases, a bone marrow biopsy may be necessary to evaluate the bone marrow's ability to produce WBCs 2.