## 4 Poster Presentations
### P-02. Dried Blood Spot Contamination--An Underestimate Risk in Newborn Screening  
[PERSON] 1, [PERSON] 1, [PERSON] 2 and [PERSON] 1  
1 Institut for Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Germany 2 Hospital for Paediatric and Adolescent Medicine, University Medicine Greifswald, Germany  
Objectives: Filter paper with dried blood is the standard specimen used for newborn screening all around the world. Convenient transportation via regular mail and the reasonable stability of metabolites of interest support its use. The heel pick procedure, as the method of sample acquisition, is well standardized. The use of native blood without anticoagulants (e.g., EDTA) is required since they are known to interfere with screening laboratory methods. However, other invisible contamination of the filter paper, prior, during, or after sample collection are often not visually detectable and do have, nevertheless, a significant influence on the screening results. In order to emphasize the correct pre-analytical phase within newborn screening, eight different contamination sources, which are present in our neonatal ward, were evaluated in terms of their impact on the screening results. Methods: Capillary blood was obtained from 10 volunteers and applied to screening filter papers. Afterwards, separate spots were intentionally contaminated with either (1) disinfectant; (2) feces; (3) urine; (4) baby cream; (5) baby food; (6) ultrasonic gel; (7) breast milk; and (8) baby wipes. One spot was not contaminated for control purposes. TSH, 17-OHP, GALT, Biotinidase, IRT, amino acids and acylcarnitines were analyzed. Results: All contaminants affected in some way the analysis. Most pronounced were the false positive effects of feces on IRT, of urine on the Glutaric acidemia type I analyte C5 DC and baby cream on GALT activity. Conclusions: Mishandling of filter papers in the pre-analytical phase is a source of false positive and false negative screening results and underlines the importance of regular training of the medical staff involved in the screening process. +++ ==ERROR: No output for this page==
_P-03. Why to Choose a CF Reference Center for Sweat Testing in NBS Positive Babies?_  
[PERSON] 1; Project group Newborn Screening  
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succcinylacetone in dried blood spots. Both approaches are commonly used in screening programs. The German Federal Joint Committee (G-BA) is considering including tyrosinaseiaemia type I in an expanded newborn screening program and commissioned IQWiG to assess the benefits of newborn screening for tyrosineaemia type I versus no screening. Methods: IQWiG is conducting a systematic literature review in MEDLINE, Embase, and Cochrane. The primary aim is to identify intervention studies on the whole screening chain. The investigated screening test consists of using dried blood spots and measuring succinylacetone levels via tandem mass spectrometry. Ideally, prospective comparative intervention studies can be identified, where the participants are randomly allocated to a strategy, with or without application of the screening test (randomized controlled trials, RCTs). If no RCTs are identified, studies of a lower evidence level, such as non-randomized comparative studies or comparative cohort studies (either with retrospective or historical comparators), are also included. Regardless of the type of intervention study, patient-relevant outcomes are analyzed, including mortality, morbidity, hospitalization, developmental disorders, adverse events, and health-related quality of life. If evidence from the above studies is insufficient, assessment of single components of the screening chain is considered. Therefore, intervention studies comparing an earlier and later start of therapy, as well as test accuracy studies, are needed. Because of the rarity of the disease and the assumption that newborn screening shows a dramatic effect, retrospective comparative cohort studies and historically controlled studies are included as intervention studies.