Bacterial reverse mutation test (Ames) for genotoxicity evaluation

ISO 10993-3 is an internationally recognized standard for evaluating the potential of medical devices and their components to cause irreversible genetic damage during clinical use. A genotoxicity assessment performed in accordance with the standard is generally required for devices that come into the following types of contact with the human body: Prolonged (>24 h to 30 d) or long-term (>30 d) contact with tissues, bone, or dentin, Long-term contact with mucosal membranes or breached surfaces, Long-term indirect contact with blood, Contact of any duration with circulating blood. The assessment includes a review of existing safety data, such as results from chemical characterization and toxicological studies. Testing is required if existing data do not adequately address all potential risks.  Genotoxicity tests evaluate the potential of the device to induce gene mutations or chromosomal damage. As a single test cannot detect all genotoxins, the evaluation should include at least two in vitro tests: A bacterial reverse mutation test (Ames) is typically performed first as a quick screening test., Another in vitro assay, such as the Mouse Lymphoma Assay (MLA) or the Mammalian Cell Micronucleus test (MNT), is then performed to capture genotoxic compounds not detected in the Ames test.. Further in vitro or in vivo tests, such as in vivo chromosomal aberration (OECD 473) or in vivo transgenic rodent mutagenicity (OECD 488) assays, may be required if genotoxic effects are observed in the initial two in vitro tests. Test selection depends on several factors, including device type, contact category, exposure duration, market area, and possible cytotoxicity of device extracts. Measurlabs provides both the genotoxicity tests listed above and expert support for drafting a testing plan. You can contact us using the form below to get a quote. Please note that the methods can also be adapted for other sample types, including pharmaceuticals, chemicals, and novel food ingredients.

In vitro assessment of skin sensitization potential using the human Cell Line Activation Test (h-CLAT) outlined in OECD Test Guideline 442E. Testing can be performed under GLP conditions. We offer this test primarily for liquid medical devices, but other chemicals can also be analyzed. Results can be used for UN GHS skin sensitizer classification, and they can support skin sensitization hazard assessments within the ISO 10993 biological evaluation framework. Testing is performed in two steps: first, a dose-finding assay with cytotoxicity assessment identifies appropriate non- or sub-cytotoxic concentrations. The main assay then measures CD86 and CD54 surface marker expression by flow cytometry using fluorochrome-tagged antibodies. Results are expressed as relative fluorescence intensity (RFI) versus the solvent control and interpreted using the h-CLAT prediction model to yield a Positive (GHS Category 1 sensitizer) or Negative classification.

The mouse lymphoma assay (OECD 490) is an in vitro method for studying the potential mutagenicity of medical devices on mammalian cells. Together with the Ames test, it is an FDA-recommended method for assessing the genotoxic potential of medical devices under ISO 10993-3. In MLA, mouse cell lines are exposed to the extract of the test item in the presence and absence of metabolic activation. The cells are then presented to the selectively cytotoxic agent trifluorothymidine. Only mutated cells survive the exposure and form colonies, whereas normal cells do not. An increased number of colonies compared to the negative controls indicates potential mutagenicity. Measurlabs can support medical device manufacturers with the full genotoxicity evaluation. Please get in touch with our experts for a quote.

Assessment of skin corrosion hazard using a reconstructed human epidermis (RhE) model in accordance with OECD Test Guideline 431. The method determines whether a test substance is corrosive or non-corrosive and, where supported by the data, assigns UN GHS subcategories (1A, 1B, or 1C). RhE tissues are treated topically with the test substance under short and longer exposure conditions. Tissue viability is measured by the MTT assay, in which MTT is converted to formazan and quantified spectrophotometrically as percent viability relative to a negative control. For colored substances or substances that directly reduce MTT, HPLC/UPLC spectrophotometry is used to quantify the MTT formazan peak area and eliminate interference. Appropriate controls for non-specific MTT reduction and color interference are included where required. Results are reported as percent viability for each replicate and mean values across replicates, with coefficients of variation, and interpreted against the prediction model cut-offs defined in OECD TG 431. The test report states the hazard conclusion — corrosive or non-corrosive, with subcategory where applicable — alongside the supporting numerical data. Data generated under OECD 431 are accepted for UN GHS hazard classification and labeling, REACH dossier submissions, and EU CLP classification.

The purpose of reprocessing validation studies is to show that reusable medical devices can be reprocessed effectively between uses so that patients are not exposed to pathogens. Depending on the device’s intended use and classification, appropriate reprocessing steps may include cleaning, disinfection, and/or sterilization. For cleaning validation, more specifically, the testing procedure consists of three steps: Simulated contamination with artificial soils that accurately reflect clinically relevant soils, such as blood and other bodily fluids. , Cleaning (manual and/or automated), carefully following the manufacturer's instructions for parameters such as detergents, cleaning tools, water quality, and temperature. , Inspection, both visually and using quantitative methods relevant to the test soil (e.g., proteins, total organic carbon, or hemoglobin), to assess whether residual contaminants remain on the device.. Successful cleaning validation is often sufficient for non-critical reusable devices, such as blood pressure cuffs, monitors, and clutches. Semi-critical and critical devices will require further disinfection and/or sterilization validation studies, which we can also offer. The displayed example price covers a manual cleaning validation study with 6 reprocessing cycles and cleanability evaluations with visual inspection & protein content measurement. Test protocol formulation and reporting are also included.

ISO 10993-23 is an internationally recognized standard for assessing the irritation potential of medical devices that come into contact with skin, mucosal membranes, or subcutaneous tissues. Irritation tests performed according to the standard are commonly required to demonstrate compliance with EU MDR and FDA requirements with regard to biocompatibility. The appropriate testing approach is chosen based on the body contact site: Skin irritation tests evaluate whether a medical device or material causes localized skin irritation in direct contact with the skin. Testing can be conducted using in vivo or in vitro methods, depending on the device and the market area., Intracutaneous reactivity tests apply to medical devices or materials that penetrate the skin or come into contact with deeper tissues. The goal is to determine whether device extracts cause localized inflammatory responses in the dermis or subcutaneous layers.. The device itself is tested with a direct contact method, where possible. Alternatively, polar and non-polar solvents are used to prepare extracts that simulate potential leachables from the device. The displayed example price includes an in vivo direct skin irritation test performed under GLP. For a more accurate quote, do not hesitate to contact us with a description of your device and any additional requirements you may have for testing (e.g., market area, quality systems, in vivo vs. in vitro methods).

Assessment of skin sensitization potential using the ARE-Nrf2 luciferase test method outlined in OECD Test Guideline 442D and listed in Annex C of ISO 10993-10 as an in-vitro alternative to traditional in vivo sensitization tests. The method has been validated for medical device extracts. The assay models the keratinocyte activation pathway — key event 2 in the skin sensitization adverse outcome pathway (AOP) as described by the OECD. Human keratinocytes are exposed to the test substance at a range of concentrations. If the substance has skin sensitization potential, it activates the Nrf2 transcription factor, which binds to the antioxidant response element (ARE) and induces luciferase expression. The measured luciferase activity thus correlates with the sensitization potential of the substance. According to Annex C of ISO 10993-10, a substance is classified as a skin sensitizer if luciferase activity increases by 50% relative to the solvent control at a concentration where cell viability is not significantly reduced. Two extracts (one polar and one non-polar) are prepared per tested device, and testing is performed in duplicate for each solvent.

We offer comprehensive test packages for verifying the quality of type II and type IIR face masks according to the EN 14683 standard. The tests included in the packages are required to label face masks with the CE marking. Medical face masks are divided into Types I and II according to their bacterial filtration efficiency. Type I masks are not intended for healthcare professionals, but for the public to prevent the spread of infectious diseases. Type II masks are further classified based on whether they are splash-resistant (Type IIR) or not (Type II). To comply with the European Standard EN 14683, Type II face masks must undergo the following quality tests: Bacterial filtration efficiency (BFE) - The ability of the face mask to filter the bacterium Staphylococcus aureus. The BFE is expressed as the percentage of colony-forming units (cfu) that have passed via aerosol through the facemask. If a face mask consists of two or more areas with different characteristics, these areas will be tested separately., Breathability (Differential pressure) - The amount of differential pressure required to draw air through a measured surface area at a constant flow rate., Microbial cleanliness (Bioburden) - The measurement of colony forming units per gram as per EN ISO 11737-1., Biocompatibility - The medical face mask manufacturer shall complete a biocompatibility evaluation according to ISO 10993-1 as a surface device with limited contact. The applicable toxicology testing regimen shall also be determined.. In addition to the above, Type IIR masks require the following test: Splash resistance - Performed according to ISO 22609, this test determines the ability of a face mask to resist penetration of splashes of liquid at different pressures.. The lower displayed price applies to the Type II mask test package, while the higher price also includes the splash resistance test required for Type IIR masks.

The biocompatibility of medical devices with breathing gas pathways is generally assessed according to ISO 18562 standards. Measurlabs offers tests according to this standard family, including the following: ISO 18562-2: Tests for emissions of particulate matter (PM), ISO 18562-3: Tests for emissions of volatile organic substances (VOS), ISO 18562-4: Tests for condensate volume and leachables from condensate. Our experts are happy to help with any questions related to the tests and prepare a quote for you. Describe your testing needs using the form below, and we will get back to you shortly.

The 48-hour acute daphnid immobilisation test according to OECD 202 assesses short-term aquatic toxicity by measuring immobilisation of daphnids, usually Daphnia magna, and using those observations to derive concentration–response values. The primary reported metric is the EC50 at 48 hours, with an optional EC50 at 24 hours calculated from dose–response analysis. The protocol is the following: The test begins with neonates less than 24 hours old exposed for 48 hours to at least five concentrations plus a control, with a minimum of twenty animals per concentration typically arranged in replicate groups (for example, four replicates of five). , Immobilisation is observed and recorded at 24 and 48 hours, and the numbers or proportions immobilised at each concentration and in the control are tabulated for statistical modelling. , Test solutions are prepared by diluting the substance into acceptable test water, avoiding solvents or emulsifiers when possible. Analytical measurements of test substance concentration, dissolved oxygen, and pH are performed at the start and end of the exposure to document conditions. , The biological endpoint is direct observation of loss of swimming activity consistent with immobilisation, EC50 values are derived from dose–response modelling and are normally reported in concentration units such as mg/L.. The report includes the counts or proportions immobilised per concentration and control at each time point, the calculated EC50(s), and supporting water chemistry and analytical concentration data. The method is accepted under REACH for aquatic hazard characterization in registration dossiers submitted to ECHA, where OECD TG 202 is equivalent to EU Method C.2 under Commission Regulation (EC) No. 440/2008. Under the U.S. Toxic Substances Control Act (TSCA), EPA may require daphnid acute toxicity testing to OPPTS 850.1010/OECD 202 for new chemical substances expected to be acutely toxic.