For chromosomal abnormalities, there are three main types of test available. 1. Oscar Test - done from 11 to 14 weeks of gestation. It involves a blood test and scan of the fetal nuchal translucency and nasal bone. Accuracy of the test is between 80 to 85%. 2. Triple Test - This is a blood test and together with the nuchal translucency test, the accuracy is between 80 to 85%. 3. NIPT (Non-invasive Prenatal Test) - It is a blood test at present done overseas, giving an accuracy of 98 to 99% and can also tell the sex of the baby with a similar accuracy. Screening tests include fetal abnormality scan at 20 weeks of gestation and oral glucose tolerance test at 24 to 28 weeks of gestation.