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**Overview**: C3 C4 Complement Panel**Introduction**: The C3 C4 Complement Panel is a diagnostic tool designed to assess complement system using serum samples. In India, complement deficiencies or consumption occur in SLE (low C3/C4 in active disease), infections, glomerulonephritis, and autoimmune disorders. High burden in SLE (prevalence 3-10 per 100,000) and post-streptococcal GN. High morbidity from underdiagnosis in rural areas, limited immunology testing, delayed immunosuppression leading to organ damage. Per immunology practices aligned with ICMR guidelines, the test employs immunoassay for C3/C4 levels over 1-2 days with high sensitivity/specificity, valuable for monitoring disease activity. This diagnostic falls under complement screening and targets patients with suspected autoimmune or renal disorders, addressing accurate detection to guide therapy. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling precise monitoring and reducing complications. Its serum-based approach ensures reliable detection.**Other Names**: C3 C4 Pnl.**FDA Status**: FDA approved, CLIA certified for immunology, compliant with 2025 standards.**Historical Milestone**: Complement levels standard; in India, used in SLE/renal clinics.**Purpose**: The test assesses 2 parameters including C3 and C4 to guide complement evaluation, detect consumption, inform autoimmune management.**Test Parameters**: 1. C3, 2. C4.**Pretest Condition**: No fasting required; patients should report joint pain, rash, renal symptoms, or SLE suspicion.**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 SLE symptoms, renal issues, infections, family autoimmune history.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of untreated disorders including organ damage, benefits of monitoring, and minimal discomfort from venipuncture.**Procedural Considerations**: The test involves sample processing using immunoassay 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 concurrent infections can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: Low C3/C4 indicates active autoimmune disease, necessitating specialist input. Normal may require follow-up if symptoms persist.**Specialist Consultation**: Rheumatologists or nephrologists should be consulted for management.**Additional Supporting Tests**: ANA, dsDNA for confirmation.**Test Limitations**: Levels may fluctuate; comprehensive approach required.**References**: Indian Journal of Rheumatology 2024, Complement Studies India 2023. |
