Standardized Procedural Practices of the Ontario Prenatal Screening Program for aneuploidies and open neural tube defects

Background/ObjectivesThe Ontario Prenatal Screening Program (OPSP) follows internationally recognized standardized procedures for laboratories and genetics clinics. However, it has been found that some procedures are subject to interpretation, so the current procedures are designed to facilitate a unified approach in the interpretation of literature recommendations. In Ontario, the OPSP offers multiple screening modalities with integrated prenatal screening (including both first and second trimester markers) being the most commonly chosen option. Other screening modalities include first trimester screening, second trimester quad screening, serum integrated screening, and NT-Quad.MethodsThe standardization was based on a literature review and on current practices in Ontario.Results/discussionThe main finding of the review was a paucity of published data relating to the procedures and the decision-making processes involved in prenatal screening. The purpose of this publication is to provide the most up-to-date and pertinent information for clinical laboratory professionals involved with prenatal screening for Down syndrome, trisomy 18 and open neural tube defects.     

Effect of immune pressure on hepatitis C virus evolution: insights from a single-source outbreak

The incidence of liver disease progression among subjects with histologically advanced but compensated chronic hepatitis C is incomplete. The Hepatitis C Antiviral Long-term Treatment against Cirrhosis Trial was a randomized study of 3.5 years of maintenance peginterferon treatment on liver disease progression among patients who had not cleared virus on peginterferon and ribavirin therapy. Patients were followed subsequently off therapy. Because maintenance peginterferon treatment did not alter liver disease progression, we analyzed treated and control patients together. Among 1,050 subjects (60% advanced fibrosis, 40% cirrhosis), we determined the rate of progression to cirrhosis over 4 years and of clinical outcomes over 8 years. Among patients with fibrosis, the incidence of cirrhosis was 9.9% per year. Six hundred seventy-nine clinical outcomes occurred among 329 subjects. Initial clinical outcomes occurred more frequently among subjects with cirrhosis (7.5% per year) than subjects with fibrosis (3.3% per year) (P<0.0001). Child-Turcotte-Pugh (CTP) score≥7 was the most common first outcome, followed by hepatocellular carcinoma. Following occurrence of a CTP score≥7, the rate of subsequent events increased to 12.9% per year, including a death rate of 10% per year. Age and sex did not influence outcome rates. Baseline platelet count was a strong predictor of all clinical outcomes. During the 8 years of follow-up, death or liver transplantation occurred among 12.2% of patients with advanced fibrosis and 31.5% of those with cirrhosis. CONCLUSION: Among patients with advanced hepatitis C who failed peginterferon and ribavirin therapy, the rate of liver-related outcomes, including death and liver transplantation, is high, especially once the CTP score reaches at least 7.