Overview: Absolute Neutrophil Count Test
Introduction: The Absolute Neutrophil Count Test measures neutrophils, a type of white blood cell, to detect infections, inflammation, or blood disorders causing symptoms like fever, fatigue, or frequent illnesses. Following 2023 hematology guidelines, it uses flow cytometry for precise counting, aiding in identifying infectious or hematologic conditions. This test is critical for guiding antibiotic or immunosuppressive therapies, preventing complications, and improving outcomes in hematology.

Other Names: ANC Test, Neutrophil Count Assay.

FDA Status: Laboratory-developed test (LDT), meeting hematology standards for diagnostic accuracy.

Historical Milestone: Neutrophil counting began in the early 1900s with microscopy. Flow cytometry in the 1980s improved precision, and by the 2000s, automated systems enhanced clinical utility for infection diagnostics.

Purpose: Diagnoses infections, inflammation, or blood disorders, guides therapy, and monitors disease in patients with symptoms like fever or fatigue.

Test Parameters: 1. Absolute Neutrophil Count

Pretest Condition: No fasting required. Collect whole blood at any time. Report symptoms like fever, infections, or medications (e.g., chemotherapy) affecting neutrophils.

Specimen: 2-5 mL whole blood (EDTA tube). Transport in a biohazard bag within 24 hours at room temperature to preserve cell integrity.

Sample Stability at Room Temperature: 24 hours

Sample Stability at Refrigeration: 48 hours

Sample Stability at Frozen: Not frozen, as cells may lyse.

Medical History: Document fever, infections, or family history of blood disorders. Include current medications, especially chemotherapy or steroids.

Consent: Written consent required, explaining the test's purpose, diagnostic implications, and potential treatment needs.

Procedural Considerations: Uses flow cytometry to count neutrophils. Results are available in 1-2 days, enabling rapid clinical decisions.

Factors Affecting Result Accuracy: Chemotherapy or steroids may suppress neutrophil counts. Hemolysis or improper storage can degrade samples. Recent infections may elevate counts.

Clinical Significance: Low neutrophil counts indicate neutropenia, increasing infection risk. Elevated counts suggest acute infections or inflammation, prompting targeted therapy.

Specialist Consultation: Consult a hematologist or infectious disease specialist for result interpretation. Oncology referral is advised for suspected malignancies.

Additional Supporting Tests: Blood culture, C-reactive protein, or bone marrow biopsy to confirm underlying causes.

Test Limitations: Transient changes require clinical correlation. Non-specific neutrophilia or neutropenia may need repeat testing.

References: American Society of Hematology Guidelines, 2023; Boxer LA, New England Journal of Medicine, 2022.