scope:

This report discusses the detection of Pompe disease (PD), also known as glycogen storage disease type II, by population-based newborn dried blood spot (DBS) screening, and focuses on enzyme activity assays for detecting PD. It is intended to provide information for incorporating PD newborn DBS screening into the routine operations of existing newborn screening (NBS) programs.

This report includes background information on the biological and clinical features of PD, a lysosomal storage disorder (LSD). It provides descriptions of the different enzyme activity assays for PD and discusses preanalytical, analytical, and postanalytical issues for laboratory practices (see Subchapter 1.4.1). Also, the report includes a discussion of short-term and long-term follow-up (LTFU) procedures, including case tracking, as well as the diagnostic tests needed to confirm a PD diagnosis. It contains limited discussion of LSDs other than PD for which DBS-based enzyme activity assays exist, including Gaucher disease, Fabry disease, Krabbe disease, and Niemann-Pick disease type A/B.

The intended users of this report are NBS laboratory personnel, public health program personnel, followup programs, health care professionals, those involved with oversight of NBS testing, and manufacturers of NBS instruments, reagents, and related products.

This report does not cover:

• DBS specimen collection for PD newborn DBS screening (see CLSI document NBS01⁵)
• Enzyme activity assays for newborn DBS screening of LSDs other than PD
• Immunoreactive assays for LSD detection,6 because the reagents are not generally available
• Method performance comparisons of assays currently used for PD newborn DBS screening