Final answer:
Patients can be excluded from donating blood if they have systemic disorders, undergo immunosuppressive treatments, or have experienced prolonged critical illness.
Step-by-step explanation:
There are several factors that can exclude a patient from donating blood:
- Systemic disorders: Patients with conditions such as diabetes mellitus, malnutrition, hepatitis, or HIV infection are usually excluded from donating blood.
- Immunosuppressive treatments: Patients who have undergone treatments like cytotoxic chemotherapy, bone marrow ablation, or radiation therapy are usually excluded from donating blood.
- Prolonged critical illness: Patients who have experienced prolonged critical illness due to infection, surgery, or trauma, especially in the very young, elderly, or hospitalized patients, are usually excluded from donating blood.
These exclusions are in place to ensure the safety of both the donor and the recipient of the blood.