Formalin, an aqueous solution of formaldehyde, has been the gold standard for fixation of histological samples for over a century. Despite its considerable advantages, growing evidence points to objective toxicity, particularly highlighting its carcinogenicity and mutagenic effects. In 2016, European Union proposed a ban, but a temporary permission was granted in consideration of its fundamental role in the medical-diagnostic field. In the present study, we tested an innovative fixative, Glyoxal Acid-Free (GAF) (a glyoxal solution deprived of acids), which allows optimal tissue fixation at structural and molecular level combined with the absence of toxicity and carcinogenic activity. An open label, non-inferiority, multicentric trial was performed comparing fixation of histological specimens with GAF fixative vs standard Phosphate Buffered Formalin (PBF), evaluating the morphological preservation and the diagnostic value with four binary score questions answered by both the central pathology reviewer and local centre reviewers. The mean of total score in the GAF vs PBF fixative groups was 3.7+/-0.5 vs 3.9+/-0.3 for the central reviewer and 3.8+/-0.5 vs 4.0+/-0.1 for the local pathologist reviewers, respectively. In terms of median value, similar results were observed between the two fixative groups, with a median value of 4.0. Data collected indicate the non-inferiority of GAF as compared to PBF for all organ tested. The present clinical performance study, performed following the international standard for performance evaluation of in vitro diagnostic medical devices, highlights the capability of GAF to ensure both, structural preservation and diagnostic value of the preparations.

PD is an employee of Addax Biosciences srl. GB and BB are co-founder of Addax Biosciences srl.

The study was supported by Piedmont Region, European Funds for Regional Development (POR FESR 2014-2020) trough Addax Biosciences.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The protocol and all the study-related documents were approved by the local Ethical Committees (IRCCS Candiolo, Prot.269/2019, Italy; Comite de Eticade Investigacion, Pr 422/2019, Spain; Manchester Cancer Research Centre Biobank, ref: 18/NW/009, UK) before the beginning of the trial. All patients signed an informed consent prior to their participation in the study.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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Yes

All data produced in the present work are contained in the manuscript or in the supplementary results, or in online databases whose link is present in the manuscript.

https://addax.crs4.it/datasets/1