What is the main purpose of collecting a 'crossmatch' sample?

The primary purpose of collecting a 'crossmatch' sample is to determine compatibility for blood transfusions. This process involves mixing a sample of the patient's blood with a sample of donor blood to see if there is any reaction. A successful crossmatch ensures that the recipient’s immune system will not react negatively to the donor blood, which is critical for preventing transfusion reactions.

In blood transfusion practices, ensuring compatibility helps to avoid serious complications that can arise when incompatible blood types are mixed. It is a critical step in ensuring patient safety during transfusions, which is why it is emphasized in phlebotomy and transfusion medicine training.

The other choices relate to different medical assessments that do not involve compatibility for transfusions, such as genetic disorders, liver function evaluation, or cholesterol analysis. Each of these tests serves a unique role in healthcare, but they are not relevant to the purpose of a crossmatch sample.