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**Overview**: Fractional Excretion Sodium Panel**Introduction**: The Fractional Excretion Sodium Panel is a diagnostic tool designed to assess renal sodium handling using serum and urine samples. In India, FENa helps differentiate pre-renal from intrinsic acute kidney injury (AKI) in sepsis, dehydration, or nephrotoxic causes, with high utility in tropical diseases (dengue, malaria) causing AKI. High morbidity from under-testing in rural/low-SES patients with oliguria, limited renal labs, delayed fluid management leading to progression or dialysis need. Per nephrology practices aligned with ICMR and Indian Society of Nephrology guidelines, the test employs spectrophotometry for serum/urine sodium/creatinine and FENa calculation over 1-2 days with high accuracy, valuable for AKI workup in resource-limited settings. This diagnostic falls under renal function screening and targets patients with AKI or oliguria, addressing accurate detection to guide fluid resuscitation or diuretics. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling precise renal assessment and reducing AKI complications. Its serum/urine-based approach ensures reliable calculation.**Other Names**: FENa Pnl.**FDA Status**: FDA approved, CLIA certified for biochemistry, compliant with 2025 standards.**Historical Milestone**: FENa standard for AKI; in India, used in critical care/nephrology.**Purpose**: The test assesses 5 parameters including serum sodium to calculate FENa, guide renal sodium handling evaluation, differentiate AKI etiology.**Test Parameters**: 1. Serum Sodium, 2. Urine Sodium, 3. Serum Creatinine, 4. Urine Creatinine, 5. FENa.**Pretest Condition**: Fasting 10-12 hours recommended; patients should have AKI suspicion.**Specimen**: 3 mL serum in 1 SST and 10 mL urine in sterile container, transported within specified times to maintain sample viability.Sample Stability: Serum 8 H(s) RT / 7 D(s) refrigerated / 6 M(s) frozen; Urine 24 H(s) RT / 7 D(s) refrigerated / 6 M(s) frozen.**Medical History**: Patients should provide details on urine output, dehydration, sepsis.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of untreated AKI including dialysis need, benefits of early assessment, and minimal discomfort from collection.**Procedural Considerations**: The test involves sample processing using spectrophotometry by trained personnel to ensure sterile technique, avoid hemolysis, and calculate FENa within 1-2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.**Factors Affecting Result Accuracy**: Diuretics, improper collection, or delays can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: Low FENa (<1 percent) suggests pre-renal AKI; high (>2 percent) intrinsic, necessitating specialist input.**Specialist Consultation**: Nephrologists should be consulted for management.**Additional Supporting Tests**: FEUrea, urine microscopy for confirmation.**Test Limitations**: Influenced by diuretics; comprehensive approach required.**References**: Indian Journal of Nephrology 2024, AKI Studies India 2023. |
