Table 2.

FDA framework for the evaluation of biocompatibility in device development.

Contact Duration	Type of Device	Nature of Body Contact	Recommended Endpoint Testing
Limited contact (≤24 h)	Surface device	Intact skin	C, S, and I
		Mucosal membrane	C, S, and I
		Breached or compromised surface	C, S, I, Sy, and P
	External communicating device	Blood path, indirect	C, S, I, Sy, P, and H
		Tissue/bone/dentin	C, S, I, Sy, and P
		Circulating blood	C, S, I, Sy, P, G, and H
	Implant device	Tissue/bone	C, S, I, Sy, and P
		Blood	C, S, I, Sy, P, G, Im, and H
Prolonged contact (>24 h to ≤30 days)	Surface device	Intact skin	C, S, and I
		Mucosal membrane	C, S, I, Sy, P, Sub, and Im
		Breached or compromised surface	C, S, I, Sy, P, Sub, and Im
	External communicating device	Blood path, indirect	C, S, I, Sy, P, Sub, and H
		Tissue/bone/dentin	C, S, I, Sy, P, Sub, G, and Im
		Circulating blood	C, S, I, Sy, P, Sub, G, Im, and H
	Implant device	Tissue/bone	C, S, I, Sy, P, Sub, G, and Im
		Blood	C, S, I, Sy, P, Sub, G, Im, and H
Long-term/ permanent contact (>30 days)	Surface device	Intact skin	C, S, and I
		Mucosal membrane	C, S, I, Sy, P, Sub, G, Im, and Ct
		Breached or compromised surface	C, S, I, Sy, P, Sub, G, Im, Ct, and Car
	External communicating device	Blood path, indirect	C, S, I, Sy, P, Sub, G, Im, Ct, and Car
		Tissue/bone/dentin	C, S, I, Sy, P, Sub, G, Im, Ct, Car, and H
		Circulating blood	C, S, I, Sy, P, Sub, G, Im, Ct, and Car
	Implant device	Tissue/bone	C, S, I, Sy, P, Sub, G, Im, Ct, and Car
		Blood	C, S, I, Sy, P, Sub, G, Im, Ct, Car, and H

C (cytotoxicity), S (sensitization), I (irritation or intracutaneous reactivity), Sy (acute systemic toxicity), P (material-mediated pyrogenicity), H (hemocompatibility), G (genotoxicity), Im (implantation), Sub (subacute/subchronic toxicity), Ct (chronic toxicity), and Car (carcinogenicity).