4.1 This practice is useful for assessing cytotoxic potential both when evaluating new materials or formulations for possible use in medical applications, and as part of a quality control program for established medical materials and medical devices.

4.2 This practice assumes that assessment of cytotoxicity potential provides one method for predicting the potential for cytotoxic or necrotic reactions to medical materials and devices during clinical applications to humans. In general, cell culture testing methods have shown good correlation with animal assays and are frequently more sensitive to toxic moieties.

4.3 This cell culture test method is suitable for adoption in specifications and standards for materials for use in the construction of medical devices that are intended to be implanted in the human body or placed in contact with tissue, tissue fluids, or blood on a long-term basis. However, care should be taken when testing materials that are resorbable to be sure the method is applicable.

4.4 Since cells in this direct contact test method are not protected by an overlying agarose layer, they are more susceptible to potential mechanical damage imparted by the overlying test sample. Investigators wishing to evaluate the cytotoxic response of cells underlying the test sample should consider agarose-based methods similar to Test Method F895. Alternatively, depending on sample characteristics, extraction methods such as Practice F619 may also be considered.

1.1 This practice covers a reference method of direct contact cell culture testing which may be used in evaluating the cytotoxic potential of materials for use in the construction of medical materials and devices.

1.2 This practice may be used either directly to evaluate materials or as a reference against which other cytotoxicity test methods may be compared.

1.3 This is one of a series of reference test methods for the assessment of cytotoxic potential, employing different techniques.

1.4 Assessment of cytotoxicity is one of several tests employed in determining the biological response to a material, as recommended in Practice F748.

1.5 The L-929 cell line was chosen because it has a significant history of use in assays of this type. This is not intended to imply that its use is preferred; only that the L-929 is a well-characterized, readily available, established cell line that has demonstrated reproducible results in several laboratories.

1.6 Since the test sample is not removed at the time of microscopic evaluation and underlying cells may be affected by the specific gravity of the test sample, this practice is limited to evaluation of cells outside the perimeter of the overlying test sample.

1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.