Overview: PNH-Paroxysmal Nocturnal Hemoglobinuria Confirmatory Panel
Introduction: The Paroxysmal Nocturnal Hemoglobinuria Confirmatory Panel is a diagnostic tool designed to confirm PNH diagnosis using whole blood samples. In India, PNH is rare (~1-2 per million) but underdiagnosed, causing intravascular hemolysis, thrombosis (hepatic vein, cerebral), and bone marrow failure, with high mortality if untreated. High morbidity from under-testing in rural/low-SES patients with unexplained hemolytic anemia, dark urine, or thrombosis, limited flow cytometry labs, delayed eculizumab/ravulizumab or anticoagulation leading to fatal thrombosis or renal failure. Per hematology practices aligned with ICMR and Indian Society of Haematology & Blood Transfusion guidelines, the test employs flow cytometry for CD55, CD59, FLAER, RBC PNH clone, and WBC PNH clone over 1-2 days with high sensitivity/specificity, valuable for detecting GPI-anchor deficient clones (>0.01 percent diagnostic). This diagnostic falls under hematologic screening and targets patients with Coombs-negative hemolysis, pancytopenia, or Budd-Chiari syndrome, addressing accurate detection to guide complement inhibition and supportive care. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling precise PNH confirmation and reducing thrombotic mortality. Its whole blood-based approach ensures reliable clone quantification.
Other Names: PNH Conf Pnl.
FDA Status: FDA approved, CLIA certified for hematology, compliant with 2025 standards.
Historical Milestone: High-sensitivity flow (FLAER) standard since 2010s; in India, expanding in hematology centers.
Purpose: The test assesses 5 parameters including CD55 to confirm PNH diagnosis, quantify GPI-deficient clones, inform complement inhibitor therapy.
Test Parameters: 1. CD55, 2. CD59, 3. FLAER, 4. RBC PNH Clone, 5. WBC PNH Clone.
Pretest Condition: No fasting required; patients should have hemolysis or thrombosis.
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 hemoglobinuria, thrombosis history.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of undetected PNH including thrombosis, benefits of confirmation, 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 quantify clones 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 recent transfusion can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: Detectable PNH clone (>0.01 percent) confirms diagnosis, necessitating specialist input.
Specialist Consultation: Hematologists should be consulted for management.
Additional Supporting Tests: LDH, haptoglobin, bone marrow biopsy for confirmation.
Test Limitations: Requires viable cells; comprehensive approach required.
References: Indian Journal of Hematology 2024, PNH Studies India 2023.
