The phrase "according to a protocol approved by" is correct and usable in written English.
You can use it when referencing a specific set of guidelines or procedures that have received formal approval from an authority or governing body.
Example: "The experiment was conducted according to a protocol approved by the ethics committee to ensure the safety and well-being of all participants."
Alternatives: "in accordance with a protocol sanctioned by" or "following a protocol authorized by".
All animal experiments were performed in accordance with the European Council Directive 86/609/EEC and according to a protocol approved by the Ethical Committee for Animal Testing of the University of Navarra (ref: 026/11).
All animal procedures were performed according to a protocol approved by the Yonsei University Animal Care and Use Committee, in accordance with NIH guidelines.
All animal experiments were performed according to a protocol approved by the IACUC of the Icahn School of Medicine at Mount Sinai.
Blood was drawn from healthy human volunteers according to a protocol approved by the Institutional Review Board at UCLA.
Animal studies were performed according to a protocol approved by IACUC of the University of California, Davis.
This study was conducted according to a protocol approved by the institutional review board and independent ethics committee of the National Cancer Center Hospital.
Animal experiments were performed according to a protocol approved by National Institute of Dental and Craniofacial Research's Animal Care and User Committee (ACUC) of National Institutes of Health.
The blood sample was obtained with written informed consent according to a protocol approved by the University of British Columbia Research Ethics Board.
For hUCBSC, after obtaining informed consent, human umbilical cord blood was collected from healthy volunteers according to a protocol approved by the Institutional Review Board.
Written informed consent to participate in the study and provide a skin biopsy was obtained according to a protocol approved by the "Federico II" ethics committee.
The present study was conducted in accordance with the Declaration of Helsinki guidelines, and informed consent was obtained from each individual according to a protocol approved by the Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University.
