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**Overview**: Interleukin 28B Genotyping Panel**Introduction**: The Interleukin 28B Genotyping Panel is a diagnostic tool designed to assess hepatitis C treatment response using whole blood samples. In India, chronic hepatitis C affects ~12-18 million people (~1 percent prevalence), with IL28B (now IFN lambda 3/4) polymorphisms (rs12979860 CC and rs8099917 TT) strongly predicting sustained virologic response (SVR) to pegylated interferon + ribavirin (~70-80 percent SVR in favorable genotypes vs <30 percent in unfavorable). Although DAAs have largely replaced IFN-based regimens, IL28B genotyping remains relevant in resource-limited settings, genotype 3 patients, or IFN retreatment cases. High morbidity from under-testing in rural/low-SES HCV patients, limited genetic labs, delayed appropriate regimen selection leading to treatment failure, cirrhosis progression, or HCC. Per hepatology practices aligned with ICMR and National Viral Hepatitis Control Programme guidelines, the test employs PCR for rs12979860 and rs8099917 genotypes over 1-2 days with high accuracy, valuable for prognostication in IFN-eligible cases. This diagnostic falls under genetic screening and targets chronic HCV patients (especially genotype 3 or prior IFN failure), addressing accurate detection to guide personalized therapy and resource allocation. With elevated morbidity due to under-testing, the test supports public health efforts by enabling precise response prediction and reducing HCV complications. Its whole blood-based approach ensures reliable SNP genotyping.**Other Names**: IL28B Geno Pnl.**FDA Status**: FDA approved, CLIA certified for molecular pathology, compliant with 2025 standards.**Historical Milestone**: IL28B GWAS discovery 2009; in India, used in pre-DAA era and genotype 3 cases.**Purpose**: The test assesses 2 parameters including rs12979860 genotype to guide hepatitis C treatment response prediction, stratify SVR probability, inform regimen choice.**Test Parameters**: 1. rs12979860 Genotype, 2. rs8099917 Genotype.**Pretest Condition**: No fasting required; patients should have confirmed chronic HCV.**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 DNA 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**: Not applicable (fresh sample preferred for PCR).**Medical History**: Patients should provide details on HCV genotype, prior treatment, liver function.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of poor response prediction including treatment failure, benefits of genotyping, and minimal discomfort from blood draw.**Procedural Considerations**: The test involves sample processing using PCR by trained personnel to ensure sterile technique, avoid contamination, and interpret genotypes 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 low DNA yield can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: Favorable genotypes (CC/TT) predict high SVR with IFN; unfavorable suggest DAA preference, necessitating specialist input.**Specialist Consultation**: Hepatologists should be consulted for management.**Additional Supporting Tests**: HCV RNA, genotype for confirmation.**Test Limitations**: Prognostic in IFN era; comprehensive approach required.**References**: Indian Journal of Gastroenterology 2024, HCV Studies India 2023. |
