The importance of verifying manufacturer's claim on specimen stability: An example in serum angiotensin converting enzyme testing.

Appropriate specimen handling is integral to quality and minimizing medical errors. Clinical laboratories often rely on manufacturer's claims for handling specimens, such as sample stability conditions. Serum angiotensin converting enzyme (ACE) is an example in which manufacturer claims and stability in the literature is limited. The purpose of this study was to demonstrate the importance to verify manufacturer's stability using serum ACE as an example. Serum was collected from 39 healthy volunteers and ACE activity levels measured at baseline, after 4 h, 1, 3, 7 days at room temperature, after 3, 7, and 14 days refrigerated at 4 °C, after 1, 2, 4 and 8 weeks frozen at -20 °C, and after three freeze/thaw cycles. An additional 42 discarded patient serum specimens were re-analyzed after 1 or 2 weeks frozen at -20 °C. To evaluate stability performance, percent difference was compared to the clinical acceptance criteria, which was defined as a ½ total allowable error of ±10.9 %. This study found serum ACE to be stable 4 h at room temperature, 14 days refrigerated at 4 °C, up to 1 week frozen at -20 °C, and up to three freeze/thaw cycles. The preferred storage condition for serum ACE is refrigerated at 4 °C as there was minimal change in percent bias over the 14 day period. The false increase observed in samples stored frozen longer than 1 week could impact clinical decision making. The stability findings differed from manufacturer claims, highlighting the importance of verifying stability, especially for esoteric testing such as serum ACE where specimens travel long distances in varying climates to reach centralized testing locations.

The Alberta Newborn Screening Approach for Sickle Cell Disease: The Advantages of Molecular Testing.

Sickle cell disease (SCD), a group of inherited red blood cell (RBC) disorders caused by pathogenic variants in the beta-globin gene (HBB), can cause lifelong disabilities and/or early mortality. If diagnosed early, preventative measures significantly reduce adverse outcomes related to SCD. In Alberta, Canada, SCD was added to the newborn screening (NBS) panel in April 2019. The primary conditions screened for are sickle cell anemia (HbS/S), HbS/C disease, and HbS/ß thalassemia. In this study, we retrospectively analyzed the first 19 months of SCD screening performance, as well as described our approach for screening of infants that have received a red blood cell transfusion prior to collection of NBS specimen. Hemoglobins eluted from dried blood spots were analyzed using the Bio-Rad™ VARIANT nbs analyzer (Bio-Rad Laboratories, Inc., Hercules, CA, USA). Targeted sequencing of HBB was performed concurrently in samples from all transfused infants. During the period of this study, 43 of 80,314 screened infants received a positive NBS result for SCD, and of these, 34 were confirmed by diagnostic testing, suggesting a local SCD incidence of 1:2400 births. There were 608 infants with sickle cell trait, resulting in a carrier frequency of 1:130. Over 98% of non-transfused infants received their NBS results within 10 days of age. Most of the 188 transfused infants and 2 infants who received intrauterine transfusions received their final SCD screen results within 21 ± 10 d of birth. Our SCD screening algorithm enables detection of affected newborns on the initial NBS specimen, independent of the reported blood transfusion status.

Newborn Screening: Current Status in Alberta, Canada.

Newborn screening (NBS) in Alberta is delivered by a number of government and health service entities who work together to provide newborn screening to infants born in Alberta, the Northwest Territories, and the Kitikmeot region of the Nunavut territory. The Alberta panel screens for 21 disorders (16 metabolic, two endocrine, cystic fibrosis, severe combined immunodeficiency, and sickle cell disease). NBS is a standard of care, but is not mandatory. NBS performance is monitored by the Alberta Newborn Metabolic Screening (NMS) Program and NMS Laboratory, who strive for continuous quality improvement. Performance analysis found that over 99% of registered infants in Alberta received a newborn screen and over 98% of these infants received a screen result within 10 days of age.