Category Archive

This white paper outlines the potential adverse effects of conventional blood testing and emerging approaches to mitigate and resolve this problem.

The fourth and final white paper in our series reviews several concepts of enzyme assays for lysosomal storage disorders (LSDs). To wrap up the series, Baebies examines all the factors that determine enzyme activity and highlights how enzyme assays can be performed with shorter incubation times without incurring additional cost or compromising assay performance. This is especially significant in the case of newborn screening of Pompe disease, where timely intervention results in better outcomes for the patients.

The recent additions of two lysosomal storage disorders (Pompe and MPS I) and a peroxisomal metabolic disorder (X-ALD) to the RUSP have led several labs to discuss adding these disorders to their screening panels. Our “Understanding Enzyme Assays for Lysosomal Storage Disorders” white paper series has examined key differences between enzymatic versus metabolic assays on digital microfluidics (FDA authorized) or tandem mass spectrometry (MS/MS) platforms. The series continues with a focus on the different screening methods for LSDs and X-ALD and how to optimize laboratory workflows when adding X-ALD.

Enzyme assays for lysosomal storage disorders (LSDs) are performed by using either digital microfluidics (FDA authorized) or tandem mass spectrometry (MS/MS) platforms. Part 1 of the “Understanding Enzyme Assays for Lysosomal Storage Disorders” series outlines the difference between natural and artificial substrates and how they are deployed on each platform. Although MS/MS platforms are often already installed in most labs for metabolic assays, key differences in assay protocols and workflows need to be evaluated to examine if it would be feasible to share the equipment. Part 2 of this series explains this further and examines the time it takes for each method workflow, including the steps and equipment necessary.

High throughput testing of multiple lysosomal storage disorders (LSDs) from dried blood spots can be performed using digital microfluidics (FDA authorized) or tandem mass spectrometry. Although both methods use “artificial” substrates to perform enzymatic reactions, digital microfluidics runs each reaction at its optimal pH. Download this free white paper to learn key differences between natural and artificial substrates for LSD assays and how they are deployed on each platform.

In our discussions with state public health laboratories, Baebies has observed confusion and ambiguity on the difference between Infantile Onset Pompe disease and Late Onset Pompe disease. We interviewed world-renowned expert on Pompe disease, Dr. Priya Kishnani, to disseminate insights into the clinical manifestations of Infantile Onset Pompe disease and Late Onset Pompe disease and to elucidate the significance of newborn screening for Pompe disease to public health laboratories who may be interested in adding Pompe disease to their screening panels. Dr. Kishnani is Division Chief of Medical Genetics and Director of the Y.T. and Alice Chen Pediatric Genetics and Genomics Research Center at Duke University Medical Center (DUMC). She also serves as Director of the Lysosomal Storage Disease Program, Biochemical Genetics Training Program and Metabolic Clinic at DUMC.

Newborn screening of lysosomal storage disorders (LSDs) can be performed using different methods, workflows, screening algorithms, assay protocols, reagents/kits and instruments, all of which impact the output of the test. “Equivalent cutoff” has been proposed as a method to normalize screening results across LSD screening platforms. In this white paper, we review the validity of the recently proposed “equivalent cutoff” and the critical shortcomings in the effectiveness of this idea, including how it ignores the cardinal rule of newborn screening: to minimize the chance of a false negative result.

A major goal of any newborn screening laboratory is to adopt screening methods that best identify those at-risk for a particular disorder. Although the term analytical range has recently been presented as a metric for method performance comparison for newborn screening of lysosomal storage disorders, it is a poor comparator of assay platforms. Download our free white paper to learn why Z-factor is the superior metric over analytical range when comparing newborn screening assay performance.