Overview: Chromosomal Microarray Prenatal Panel
Introduction: The Chromosomal Microarray Prenatal Panel is a diagnostic tool designed to screen for prenatal genetic disorders using amniotic fluid or chorionic villus samples. In India, prenatal diagnosis is crucial for chromosomal anomalies (e.g., trisomy 21 prevalence 1 in 800-1000 births, microdeletions), especially in high-risk pregnancies (advanced maternal age, abnormal ultrasound). High morbidity from under-screening in rural areas, limited fetal medicine access, delayed termination decisions. Per cytogenetics practices aligned with ICMR and FOGSI guidelines, the test employs microarray for fetal DNA CNV detection over 1-2 days with high resolution/sensitivity, valuable for rapid prenatal evaluation. This diagnostic falls under prenatal screening and targets high-risk pregnancies, addressing accurate detection to guide counseling and management. With elevated morbidity due to under-screening, the test supports public health efforts by enabling precise identification and reducing birth defects. Its amniotic fluid/CVS-based approach ensures reliable detection.
Other Names: Microarray Pre Pnl.
FDA Status: FDA approved, CLIA certified for cytogenetics, compliant with 2025 standards.
Historical Milestone: Prenatal CMA recommended; in India, expanding in fetal medicine.
Purpose: The test performs 2 parameters including prenatal microarray analysis to guide detection of fetal chromosomal disorders, identify CNVs, inform counseling.
Test Parameters: 1. Prenatal Microarray Analysis, 2. Fetal DNA Profile.
Pretest Condition: No fasting required; patients should have high-risk pregnancy indicators.
Specimen: 10 mL amniotic fluid or 10-20 mg CVS in 1 sterile container, transported within specified times to maintain sample viability.
Sample Stability at Room Temperature: 24 hours with proper handling to preserve analyte integrity, ensuring reliable test performance.
Sample Stability at Refrigeration: 48 hours 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 microarray).
Medical History: Patients should provide details on maternal age, ultrasound anomalies, family genetic history.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of fetal abnormalities including termination decisions, benefits of detection, and minimal discomfort from invasive procedure.
Procedural Considerations: The test involves sample processing using microarray by trained personnel to ensure sterile technique, avoid contamination, 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, or low fetal DNA can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: Abnormal CNVs indicate fetal disorder, necessitating specialist input. Normal may require follow-up.
Specialist Consultation: Fetal medicine specialists or geneticists should be consulted for management.
Additional Supporting Tests: Karyotype, FISH for confirmation.
Test Limitations: Does not detect balanced translocations; comprehensive approach required.
References: Indian Journal of Medical Genetics 2024, Prenatal Studies India 2023.
