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**Overview**: Cystatin C Panel**Introduction**: The Cystatin C Panel is a diagnostic tool designed to assess kidney function using serum samples. In India, cystatin C is a superior marker to creatinine for estimating GFR (eGFR-cys), especially in early CKD, elderly, or low muscle mass patients, less influenced by diet/muscle. CKD prevalence ~17 percent, with cystatin C aiding accurate staging. High morbidity from underdiagnosis in rural/low-SES populations, limited advanced renal testing, delayed renoprotection leading to progression. Per nephrology practices aligned with ICMR and Indian Society of Nephrology guidelines, the test employs spectrophotometry for cystatin C and eGFR calculation over 1-2 days with high accuracy, valuable for refined GFR estimation. This diagnostic falls under kidney function screening and targets patients with diabetes, hypertension, or borderline creatinine, addressing accurate detection to guide early intervention. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling precise renal assessment and reducing end-stage disease. Its serum-based approach ensures reliable detection.**Other Names**: Cystatin C Pnl.**FDA Status**: FDA approved, CLIA certified for biochemistry, compliant with 2025 standards.**Historical Milestone**: Cystatin C as alternative GFR marker; in India, useful in elderly/diabetic screening.**Purpose**: The test assesses 3 parameters including cystatin C and eGFR to guide kidney function evaluation, refine GFR estimation, inform management.**Test Parameters**: 1. Cystatin C, 2. eGFR, 3. Creatinine.**Pretest Condition**: Fasting 10-12 hours recommended; patients should report edema, fatigue, or risk factors.**Specimen**: 3 mL serum in 1 SST, transported within specified times to maintain sample viability.**Sample Stability at Room Temperature**: 8 hours with proper handling to preserve analyte integrity, 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**: 6 months at -20 degrees Celsius, allowing long-term storage for retesting, though freezing may affect some analytes.**Medical History**: Patients should provide details on urine output, swelling, diabetes, hypertension, medications.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of untreated kidney impairment including progression, benefits of early detection, and minimal discomfort from venipuncture.**Procedural Considerations**: The test involves sample processing using spectrophotometry by trained personnel to ensure sterile technique, avoid hemolysis, and interpret results within 1-2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols, and store kits according to manufacturer specifications to ensure reliability.**Factors Affecting Result Accuracy**: Delays beyond stability periods, improper storage conditions, hemolysis, or inflammation can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: Elevated cystatin C/low eGFR indicates kidney impairment, necessitating specialist input. Normal may require follow-up in high-risk individuals.**Specialist Consultation**: Nephrologists should be consulted for management.**Additional Supporting Tests**: Urine albumin/creatinine ratio for confirmation.**Test Limitations**: Cystatin C influenced by thyroid function; comprehensive approach required.**References**: Indian Journal of Nephrology 2024, CKD Studies India 2023. |
