Guidance on the Safety of Human Cells, Tissues and Organs for Transplantation Regulations: Classification of CTOs

Note: Despite having a systemic effect and being dependent on their metabolic activity for their main function, minimally manipulated lymphohematopoietic cells and islet cells intended for homologous use are regulated under the CTO regulations.

Figure 1 - Long description

Use this decision tree to help you determine whether a particular tissue or cell product falls under the scope of the CTO regulations.

Step 1: Determine if the product is for allogeneic use or autologous use. A product for autologous use does not fall under the scope of the regulations.

Step 2: Determine if the allogeneic product performs the same basic function after transplantation. If it doesn't, then the product is not for homologous use and therefore does not fall under the scope of the regulations.

Step 3: Determine if the allogeneic homologous use product is a structural or non-structural product.

For structural products, answer these 3 questions to determine how to proceed:

1. What is the intended use of the product in reconstruction, repair or replacement, as stated by the manufacturer?
2. What are the original characteristics of the tissue that are relevant to this claim?
3. Does the processing of the tissue alter these relevant original characteristics?

If processing has altered the relevant original characteristics, the product does not fall under the scope of the regulations. If processing has not altered these characteristics, you must then determine if the product has a systemic effect and depends on its metabolic activity for its primary function. If it does, the product does not fall under the scope of the regulations. If it doesn't, the product does fall under the scope of the regulations.

For non-structural products for allogeneic and homologous use, answer these 3 questions to determine how to proceed.

1. What is the intended use of the product as stated by the manufacturer?
2. What are the biological characteristics of the tissue or cells that are relevant to this claim?
3. Does the processing of the tissue or cells alter these relevant biological characteristics?

If processing has altered the relevant biological characteristics, the product does not fall under the scope of the regulations. If processing has not altered these characteristics, you must then determine if the product has a systemic effect and depends on its metabolic activity for its primary function. If it does, the product does not fall under the scope of the regulations. If it doesn't, the product does fall under the scope of the regulations.