Expanded Screening of One Million Swedish Babies with R4S and CLIR for Post-Analytical Evaluation of Data

Lene Sörensen; Ulrika von Döbeln; Henrik Åhlman; Annika Ohlsson; Martin Engvall; Karin Naess; Carolina Backman-Johansson; Yvonne Nordqvist; Anna Wedell; Rolf H Zetterström

doi:10.3390/ijns6020042

Expanded Screening of One Million Swedish Babies with R4S and CLIR for Post-Analytical Evaluation of Data

Int J Neonatal Screen. 2020 May 27;6(2):42. doi: 10.3390/ijns6020042. eCollection 2020 Jun.

Authors

Lene Sörensen^{1

2}, Ulrika von Döbeln^{1

3}, Henrik Åhlman¹, Annika Ohlsson^{1

3}, Martin Engvall^{1

2}, Karin Naess^{1

3}, Carolina Backman-Johansson¹, Yvonne Nordqvist^{1

3}, Anna Wedell^{1

2}, Rolf H Zetterström^{1

2}

Affiliations

¹ Centre for Inherited Metabolic Diseases, Karolinska University Hospital Solna, SE-171 76 Stockholm, Sweden; ulrika.vondobeln@sll.se (U.v.D.); henrik.ahlman@sll.se (H.Å.); annika.ohlsson@eskilstuna.se (A.O.); martin.engvall@sll.se (M.E.); karin.naess@ki.se (K.N.); carolina.backman-johansson@sll.se (C.B.-J.); yvonne.m.nordqvist@sll.se (Y.N.); anna.wedell@ki.se (A.W.); rolf.zetterstrom@sll.se (R.H.Z.).
² Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
³ Department of Medical Biochemistry and Biophysics, Division of Molecular Metabolism, Karolinska Institutet, SE-171 77 Stockholm, Sweden.

Abstract

Sweden has one neonatal screening laboratory, receiving 115 to 120 thousand samples per year. Among the one million babies screened by tandem mass spectrometry from November 2010 until July 2019, a total of 665 babies were recalled and 311 verified as having one of the diseases screened for with this methodology, giving a positive predictive value (PPV) of 47% and an incidence of 1:3200. The PPV was high (41%) already in the first year after start of screening, thanks to the availability of the collaborative project Region 4 Stork database. The PPV is presently 58%. This improvement was achieved by the implementation of second-tier analyses in the screening for methylmalonic aciduria, propionic aciduria, isovaleric aciduria, and homocystinuria, and the employment of various post analytical tools of the Region 4 Stork, and its successor the collaborative laboratory integrated reports.

Keywords: Collaborative Laboratory Integrated Reports (CLIR); dried blood spots (DBS); expanded screening; newborn screening; positive predictive value (PPV); post-analytical evaluation; tandem mass spectrometry.