OSMT (Ontario Society of Medical Technologists) Practice Exam

Using screw caps for tubes containing media is the best practice because they provide a secure and airtight seal, which is crucial for preserving the integrity of the media within the tube. This type of closure minimizes the risk of contamination and evaporation, which can significantly alter the chemical or biological properties of the media and impact the results of any tests conducted with it. Screw caps also allow for easier access and better ease of handling, ensuring that the media remains as undisturbed and protected as possible throughout its usage. This option aligns with laboratory standards that prioritize reliability and accuracy in test results, which can be compromised if the media is not properly sealed. In contrast, cotton plugs can allow for contaminants to enter and may not provide a consistent seal against evaporation. Similarly, slight evaporation could lead to concentration changes, thus affecting test results, making that option less desirable. Lastly, while rotating old media with new is a good practice in certain contexts, it does not specifically address the closure method, which is key for ensuring the media remains viable and uncontaminated.