ArticlePloS one2017
Stability of serum ferritin measured by immunoturbidimetric assay after storage at -80°C for several years.
Article in PloS one, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT02484274 (Iron Deficiency in Infants), which is not on this map. Cited by 3 papers.
What it found
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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.
Iron Deficiency in Infants : Population-wide Study of the Protective Role of Toddler Milk Formula
Who cites it
3 citing papers in PubMed, 4 citations in OpenAlex.
- Impact of ultra-low temperature storage on serum sIgE detection and allergic disease biobank feasibility.Scientific reports · 2023Article
- Forensic biomarkers of lethal traumatic brain injury.International journal of legal medicine · 2022Review
- Higher CSF Ferritin Heavy-Chain (Fth1) and Transferrin Predict Better Neurocognitive Performance in People with HIV.Molecular neurobiology · 2021Observational
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 4 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundIron deficiency (ID) may impair long-term neurological development when it occurs in young infants. In cohort studies, it is sometimes necessary to evaluate ID with sera kept frozen for several years. To assess ID, learned societies recommend measuring serum ferritin (SF) level combined with C-reactive protein level. The long-term stability of C-reactive protein in frozen samples is well established but not ferritin.
methodsWe measured SF level (immunoturbidimetric assay; in micrograms per liter) immediately after collection from 53 young adults recruited and followed-up in Porto, Portugal, from 2011 to 2013 (SF1), and then, in 2016 in two aliquots kept frozen at- 80°C for 3 to 5 years: one without (SF2A) and one with (SF2B) intermediate thawing in 2014. We compared SF1 to SF2A then SF2B; statistical agreement was evaluated by the Bland and Altman method and the effect of intermediate thawing by regression modelling.
resultsMean SF2A-SF1 and SF2B-SF1 differences were -2.1 (SD 7.0) and 48.9 (SD 66.9). Values for Bland and Altman 95% limits of agreement were higher for the comparison of SF2B and SF1 than SF2A and SF1: -82.2 to 179.9 and -15.8 to 11.8, respectively; the effect of thawing was highly significant (p <0.001).
conclusionsAgreement between SF values before and after 3 to 5 years of constant freezing at -80°C was in a generally accepted range, which supports the hypothesis of ferritin's stability at this temperature for a long period. In long-term storage by freezing, intermediate thawing induced a major increase in values.
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Registered trials
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