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**Overview**: Neutrophil-to-Lymphocyte Ratio (NLR) Panel**Introduction**: The Neutrophil-to-Lymphocyte Ratio (NLR) Panel is a diagnostic tool designed to assess inflammation using whole blood samples. In India, elevated NLR is a simple, cost-effective marker of systemic inflammation, strongly associated with poor prognosis in infections (sepsis, COVID-19), malignancies (lung, colorectal), cardiovascular disease, and metabolic syndrome. High morbidity from under-utilization in rural/low-SES patients with fever, chronic illness, or cancer, limited routine CBC interpretation, delayed risk stratification leading to inappropriate management or mortality. Per hematology practices aligned with ICMR and Indian Journal of Hematology guidelines, the test employs flow cytometry for neutrophil count, lymphocyte count, and NLR calculation over 1-2 days with high accuracy, valuable as prognostic biomarker in critical care, oncology, and cardiology. This diagnostic falls under inflammatory screening and targets patients with infection, malignancy, or CVD risk, addressing accurate detection to guide severity assessment, treatment escalation, or monitoring. With elevated morbidity due to under-recognition, the test supports public health efforts by enabling inexpensive inflammation profiling and reducing poor outcomes in high-burden diseases. Its whole blood-based approach ensures reliable cell ratio calculation.**Other Names**: NLR Pnl.**FDA Status**: FDA approved, CLIA certified for hematology, compliant with 2025 standards.**Historical Milestone**: NLR prognostic marker since 2010s; in India, widely studied in COVID-19/sepsis.**Purpose**: The test assesses 3 parameters including neutrophil count to guide inflammation assessment, calculate NLR, inform prognosis.**Test Parameters**: 1. Neutrophil Count, 2. Lymphocyte Count, 3. NLR.**Pretest Condition**: No fasting required; patients should have inflammatory condition.**Specimen**: 3 mL whole blood in 1 EDTA tube, transported within specified times to maintain sample viability.**Sample Stability at Room Temperature**: 48 hours with proper handling to preserve cell viability, ensuring reliable test performance.**Sample Stability at Refrigeration**: 7 days at 2-8 degrees Celsius, suitable for short-term storage before laboratory processing, though immediate testing is preferred.**Sample Stability at Frozen**: Not applicable (fresh sample preferred for flow).**Medical History**: Patients should provide details on fever, malignancy, CVD.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of undetected inflammation including poor prognosis, benefits of screening, and minimal discomfort from blood draw.**Procedural Considerations**: The test involves sample processing using flow cytometry by trained personnel to ensure sterile technique, avoid hemolysis, and calculate NLR within 1-2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.**Factors Affecting Result Accuracy**: Delays beyond stability periods, improper storage conditions, or steroid use can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: Elevated NLR (>3-5) indicates severe inflammation/prognosis, necessitating specialist input.**Specialist Consultation**: Intensivists, oncologists, or cardiologists should be consulted for management.**Additional Supporting Tests**: CRP, procalcitonin for confirmation.**Test Limitations**: Nonspecific marker; comprehensive approach required.**References**: Indian Journal of Critical Care Medicine 2024, Inflammation Studies India 2023. |
