The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians
August 27, 2026 Ā· via Europe PMC
Environmental risk factors for false-positive results in newborn screening for primary carnitine deficiency: a multicenter large-scale retrospective cohort study.
Shang Z, Liu J, Leng Q, +5 more, Xie P.
AI summary ā for doctors, generated from the abstract only
Ambient temperature during dried blood spot drying was the strongest driver of the 94% false-positive rate in newborn screening for primary carnitine deficiency.
What was studied
A multicentre retrospective cohort of 104,451 neonates screened for inherited metabolic disorders between February 2019 and June 2025, comparing 735 false-positive against 47 recall-positive cases for primary carnitine deficiency and testing environmental and procedural variables including season, drying temperature and humidity, and blood spot quality.
Key findings
- Among 782 initially screen-positive cases, the false-positive rate was 94.0% (735/782)
- Plasma C0 levels at both initial screening and reanalysis were significantly lower in the recall-positive group
- Ambient temperature during drying was the most predictive independent risk factor on multivariate analysis
- Exact odds ratios and AUC values were not reported in the abstract
Clinical relevance
This suggests that controlling the drying environment for blood spots could cut unnecessary recalls and parental anxiety in carnitine deficiency screening; it is a retrospective analysis of screening laboratory data rather than a tested intervention.
Who should care
Limitations
Retrospective multicentre design with only 47 true-positive cases for comparison, environmental exposures inferred rather than experimentally controlled, and no prospective test that modifying drying conditions reduces false positives.
If your carnitine screening recall rate seems absurdly high, the problem may be how the blood spots are dried rather than the babies.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates ā verify against the original source before acting on it.
Abstract
Objective
To identify environmental risk factors contributing to false-positive results in newborn screening for primary carnitine deficiency (PCD) and to evaluate their predictive performance.
Methods
A multicenter retrospective cohort study was conducted, including 104,451 neonates who underwent newborn screening for inherited metabolic disorders between February 2019 and June 2025. Based on initial screening, reanalysis, and genetic testing, neonates were categorized into a false-positive group (nā=ā735) and a recall-positive group (nā=ā47). Baseline data and environment-related testing information were collected, including season of blood collection, ambient temperature and humidity during the drying process, as well as the quality of the dried blood spots. Univariate and multivariate logistic regression analyses were performed to identify independent influencing factors, and receiver operating characteristic (ROC) curves were used to evaluate predictive performance.
Results
Among 782 initially screen-positive cases, the false-positive rate was 94.0% (735/782). However, plasma C0 levels at both initial screening and reanalysis were significantly lower in the recall-positive group. Ambient temperature was the most predictive independent risk factor for PCD diagnosis among multiple environmental and procedural variables identified by multivariate analysis.
Conclusion
Environmental conditions during blood spot drying can interfere with neonatal plasma C0 measurements and are major causes of false-positive results in PCD screening.
DOI
10.1080/14767058.2026.2712087
PMID
42660814
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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