Biological Evaluation

Biological evaluation is done to measure the biological compatibility of medical devices with biological systems. Evaluation is performed using a sequence of tests mentioned in many international and national standards and guidelines concerning biological evaluation. Biological evaluation is performed based on their medical device classification according to the medical device nature and duration of their anticipated contact with human tissue when in use and biological endpoints are thought to be in consideration with the medical device category.

The biological evaluation of any substance or medical device intended for use in human’s beings shall form part of a structured biological evaluation plan within a risk management process in accordance with ISO 14971. A biological evaluation plan shall be planned adequately and documented by an experienced professional.

The rigor necessary in the biological evaluation is mainly determined by the use, degree, frequency, and duration of use of the exposure and the hazards identified for the medical device or material. Testing is usually not necessary when sufficient information is already available with the medical device manufacturer to perform a risk assessment of the material and/or the medical device. The biological safety shall be evaluated by the manufacturer over the entire life-cycle of a medical device.

The risk management documentation should also specify the biological hazards associated with the medical devices. Evaluation can include both a review of relevant existing preclinical and clinical data and actual testing data held by medical device manufacturer.

Following shall be the considered during biological evaluation:

• Material of construction in medical devices
• intended additives, process contaminants and residues
• packaging materials that directly or indirectly contact the medical device can transfer chemicals to the medical device and then indirectly to the patient or clinician
• leachable substances
• degradation products
• other components and their interaction in final products
• performance and characteristic of the medical device

Biological Evaluation Plan

Biological evaluation plan is developed to ensure that all the risks are addressed, as per the ISO 10993-1:2018 the biological evaluation of any material or medical device intended for use in humans shall form part of a structured biological evaluation plan within a risk management process in accordance with ISO 14971.

Biological evaluation plan is developed prior to testing as this can minimize unnecessary testing, maintain compliance with all pertinent standards/regulations and provide evidence for the ultimate goal of ensuring product safety.

As per section B.2.2 of ISO 10993-1:2018 the biological evaluation plan should be drawn up by a knowledgeable and experienced team and include as a minimum

• arrangements for gathering of applicable information from the published literature (including information sources and search strategies), in house and supplier data and other sources in order to conduct risk analysis;
• arrangements for conducting the evaluation, including the requirement for any specific technical competencies relevant to the specific medical device application;
• arrangements for review and approval of the plan as part of the overall design control process;
• arrangements for review of the final conclusions of the evaluation and the approval of any additional testing required;
• arrangements for the final review and approval of the outcomes of the biological risk assessment, including the risk control measures applied and the documentation of any residual risks and the disclosure of residual risks through means such as product labelling.

Biological Evaluation Report

A biological evaluation report (BER) is a collective summary of biological test performed and justifications for not performed test used to demonstrate how compatible a medical device is with the human body. In other words, the BER provides evidence of a medical device’s biological safety, known as biocompatibility.

Biological evaluation report also includes;

• short description of the material or medical device including its intended use,
• the analysis of all selected literatures and data, both favorable and unfavorable,
• a critical evaluation of the hazards, associated risks and appropriate safety measures;
• a description of the methods of weighting the different papers; particular attention should be given to circumstances where there are repeated publications by the same authors, in order to avoid overweighting multiple publications of the same tests;
• a list of publications appropriately cross-referenced in the evaluation;
• Gap analysis for already available information for biological safety, rationale for why additional information isn’t needed and a statement confirming the biological risk analysis and risk controls that have been completed.

A systemic approach to a biological evaluation of medical devices as part of a risk management process