Evidence map›Paper›PMID 42275423›Full record

ArticlePloS one2026

Effect of a freeze-thaw cycle on amniotic fluid interleukin-6 concentrations in pregnancies with preterm prelabor rupture of membranes: Implications for the diagnosis of intra-amniotic inflammation.

Richard Spacek, Stepanka Bubenikova, Ivana Musilova, Nikola Kuzniciusova, Karolina Janochova, Michaela Kostelkova, Ladislava Pavlikova, Magdalena Holeckova, Marek Lubusky, Ondrej Simetka and 2 more

Abstract read
In one paragraph

Article in PloS one, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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.

2 · The registry

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.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors.

Richard SpacekDepartment of Obstetrics and Gynecology, University Hospital Ostrava, Faculty of Medicine in Ostrava, Ostrava, Czech Republic.
Stepanka BubenikovaDepartment of Midwifery, Palacky University, Faculty of Health Sciences, Olomouc, Czech Republic.
Ivana MusilovaBiomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic.
Nikola KuzniciusovaInstitute of Laboratory Medicine, University Hospital Ostrava, Faculty of Medicine in Ostrava, Ostrava, Czech Republic.
Karolina JanochovaInstitute of Laboratory Medicine, University Hospital Ostrava, Faculty of Medicine in Ostrava, Ostrava, Czech Republic.
Michaela KostelkovaInstitute of Laboratory Medicine, University Hospital Ostrava, Faculty of Medicine in Ostrava, Ostrava, Czech Republic.
Ladislava PavlikovaInstitute of Clinical Biochemistry and Diagnostics, University Hospital Hradec Kralove, Charles University, Faculty of Medicine in Hradec Kralove, Hradec Kralove, Czech Republic.
Magdalena HoleckovaInstitute of Clinical Biochemistry and Diagnostics, University Hospital Hradec Kralove, Charles University, Faculty of Medicine in Hradec Kralove, Hradec Kralove, Czech Republic.
Marek LubuskyDepartment of Obstetrics and Gynecology, University Hospital Olomouc, Palacky University, Faculty of Medicine and Dentistry in Olomouc, Olomouc, Czech Republic.ORCID https://orcid.org/0000-0003-0551-0942
Ondrej SimetkaDepartment of Obstetrics and Gynecology, University Hospital Ostrava, Faculty of Medicine in Ostrava, Ostrava, Czech Republic.
Bo JacobssonDepartment of Obstetrics and Gynecology, Institute of Clinical Science, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
Marian KacerovskyBiomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic.ORCID https://orcid.org/0000-0001-9858-7900

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivePreterm prelabor rupture of membranes (PPROM) is frequently complicated by intra-amniotic inflammation. Interleukin-6 (IL-6) measured in amniotic fluid is considered the gold-standard biomarker for the diagnosis of this condition; however, diagnostic thresholds have been derived primarily from biobanked samples. It remains unclear whether IL-6 concentrations measured in fresh amniotic fluid are directly comparable with those obtained from previously processed samples. The primary aim of this study was to compare IL-6 concentrations in fresh amniotic fluid samples with those in biobanked samples that had undergone a single freeze-thaw cycle.

methodThis retrospective study included consecutive singleton pregnancies with PPROM between 24 + 0 and 36 + 6 weeks of gestation. Amniotic fluid samples were collected on admission, prior to the administration of antibiotics and corticosteroids. IL-6 concentrations were measured in both fresh and biobanked (processed) samples using an automated electrochemiluminescence immunoassay.

resultsThe study population comprised 152 women. IL-6 concentrations in fresh and processed samples were strongly correlated (rho = 0.97; p < 0.0001). Bland-Altman analysis demonstrated a systematic bias toward higher concentrations in processed samples, with a mean ratio of 1.2, indicating that processed samples yielded on average approximately 20% higher values than fresh samples. When applying the validated diagnostic threshold of 3,000 pg/mL (established in processed samples) to fresh samples, three false-negative cases were observed. In these cases, intra-amniotic inflammation was present, but IL-6 concentrations in fresh samples were below the threshold despite corresponding processed values ≥ 3,000 pg/mL. Using intra-amniotic inflammation defined by processed samples as the reference, the diagnostic performance of the 3,000 pg/mL threshold applied to fresh samples was as follows: sensitivity 92%, specificity 100%, positive predictive value 100%, and negative predictive value 97%.

conclusionsIL-6 concentrations in fresh and processed amniotic fluid samples are highly correlated, but processed samples consistently yield higher values.

Indexed as

Amniotic FluidChorioamnionitisInterleukin-6Premature Rupture of Fetal MembranesAdultBiomarkersFemaleFreezingHumansInflammationPregnancyRetrospective StudiesBiomarkersIL6 protein, humanInterleukin-6

Identifiers

PMID42275423
PMCPMC13257975

What Socratic holds

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Registered trials

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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 Socratic graph.