ReviewJournal of inherited metabolic disease2020
Performance of laboratory tests used to measure blood phenylalanine for the monitoring of patients with phenylketonuria.
Review in Journal of inherited metabolic disease, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
20 citing papers in PubMed, 42 citations in OpenAlex.
- How Well Is Blood Phenylalanine Controlled in Maternal PKU in Europe? Results from 102 Pregnancies.Nutrients · 2026Article
- Article
- Performance of the Egoo test for phenylalanine measurement in females with phenylketonuria.Orphanet journal of rare diseases · 2025Article
- Performance properties of filter-paper used in blood spot collection devices for quantitation of phenylalanine.Bioanalysis · 2025Article
- Metabolomics and Lipidomics Explore Phenotype-Specific Molecular Signatures for Phenylketonuria.International journal of molecular sciences · 2025Article
- Development of an SI traceable value assigned amino acid matrix-matched material to underpin European external quality assessment.Analytical and bioanalytical chemistry · 2025Article
- Volumetric dried blood spots for determination of phosphatidylethanol: Validation of a liquid chromatography tandem masspectrometry method and clinical application.Drug testing and analysis · 2025Article
- Pre-analytic decrease of phenylalanine in plasma of patients with phenylketonuria treated with pegvaliase.Molecular genetics and metabolism reports · 2024Article
- Iron Porphyrin-mediated Production of Carbon Monoxide from Phenylpyruvic Acid: From Potential Therapeutic and Diagnostic Use to Physiological Implications.Medicinal chemistry research : an international journal for rapid communications on design and mechanisms of action of biologically active agents · 2024Article
- Volumetric brain reductions in adult patients with phenylketonuria and their relationship with blood phenylalanine levels.Journal of neurodevelopmental disorders · 2024Article
- Investigation of the relationship between phenylalanine in venous plasma and capillary blood using volumetric blood collection devices.JIMD reports · 2023Article
- A method for phenylalanine self-monitoring using phenylalanine ammonia-lyase and a pre-existing portable ammonia detection system.Molecular genetics and metabolism reports · 2023Article
- Differences of Phenylalanine Concentrations in Dried Blood Spots and in Plasma: Erythrocytes as a Neglected Component for This Observation.Metabolites · 2021Article
- Measurement of the alcohol biomarker phosphatidylethanol (PEth) in dried blood spots and venous blood-importance of inhibition of post-sampling formation from ethanol.Analytical and bioanalytical chemistry · 2021Article
- Urine Phenylacetylglutamine Determination in Patients with Hyperphenylalaninemia.Journal of clinical medicine · 2021Article
- Multianalyte serology in home-sampled blood enables an unbiased assessment of the immune response against SARS-CoV-2.Nature communications · 2021Article
- Human biomimetic liver microphysiology systems in drug development and precision medicine.Nature reviews. Gastroenterology & hepatology · 2021Review
- Monitoring phenylalanine concentrations in the follow-up of phenylketonuria patients: An inventory of pre-analytical and analytical variation.JIMD reports · 2021Article
- Evaluation of a Common Internal Standard Material to Reduce Inter-Laboratory Variation and Ensure the Quality, Safety and Efficacy of Expanded Newborn Screening Results When Using Flow Injection Analysis Tandem Mass Spectrometry with Internal Calibration.International journal of neonatal screening · 2020Article
- Use of Dried Blood Spot Specimens to Monitor Patients with Inherited Metabolic Disorders.International journal of neonatal screening · 2020Review
Corrections and comments
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Authors and funding
8 authors at 6 institutions in 3 countries.
Funding
Abstract
Analysis of blood phenylalanine is central to the monitoring of patients with phenylketonuria (PKU) and age-related phenylalanine target treatment-ranges (0-12 years; 120-360 μmol/L, and >12 years; 120-600 μmol/L) are recommended in order to prevent adverse neurological outcomes. These target treatment-ranges are based upon plasma phenylalanine concentrations. However, patients are routinely monitored using dried bloodspot (DBS) specimens due to the convenience of collection. Significant differences exist between phenylalanine concentrations in plasma and DBS, with phenylalanine concentrations in DBS specimens analyzed by flow-injection analysis tandem mass spectrometry reported to be 18% to 28% lower than paired plasma concentrations analyzed using ion-exchange chromatography. DBS specimens with phenylalanine concentrations of 360 and 600 μmol/L, at the critical upper-target treatment-range thresholds would be plasma equivalents of 461 and 768 μmol/L, respectively, when a reported difference of 28% is taken into account. Furthermore, analytical test imprecision and bias in conjunction with pre-analytical factors such as volume and quality of blood applied to filter paper collection devices to produce DBS specimens affect the final test results. Reporting of inaccurate patient results when comparing DBS results to target treatment-ranges based on plasma concentrations, together with inter-laboratory imprecision could have a significant impact on patient management resulting in inappropriate dietary change and potentially adverse patient outcomes. This review is intended to provide perspective on the issues related to the measurement of phenylalanine in blood specimens and to provide direction for the future needs of PKU patients to ensure reliable monitoring of metabolic control using the target treatment-ranges.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.