Which of the following actions is standard practice when collecting a blood smear?

Cleaning a slide with isopropyl alcohol and letting it dry is a standard practice when collecting a blood smear because it ensures that the slide is free from contaminants that could interfere with the staining process and the visualization of the blood cells. The use of isopropyl alcohol helps to remove any oils, dust, or residues from previous samples or handling that may remain on the slide. Allowing the slide to dry completely after cleaning is equally important, as any moisture left on the slide can affect the quality of the smear, leading to poor cellular morphology and potentially inaccurate results.

In a clinical environment, preparing a blood smear properly is crucial for accurate diagnosis and assessment of blood disorders, and thorough cleaning of the slide is a foundational step in that process. Using a plain slide without treatment may not provide the clean surface necessary for optimal results, while wiping the slide with a dry cloth could introduce lint or fibers. Heating the slide is not a common practice and can also risk damaging the slide or affecting the integrity of the blood smear.